Quite frankly, you couldn't just rehash the first season. Doug doesn't even have to take part in the combat. (though of course he would) Just teaching the Senshi to act as a cohesive and effective fighting unit would wildly unbalance the status quo. Once the Senshi start beating their opponents by more than the skin of their teeth, and then manage to trap, interrogate, and neutralize one of the Dark Kingdom Generals, things could take three directions:
1) Beryl maintains the canon strategy -- in which case it's a walk in the park for the Good Guys, very dull reading for the audience, and probably very dull writing for the author. ^^ Bonus for the fact that the Reset wouldn't occur.
2) Beryl whips her Generals in line and throws everything she has at the Senshi -- in which case one of two things happens:
a) Beryl has still got it after all those years; the Generals are Generals because they can actually lead; the Youma Hordes number large enough to actually be considered Hordes; and they've all got a can of whoopass to open even without Metallia supplying them with more. End Result: Senshi + Doug are mowed down; Japan is established as a Dark Kingdom beach head; the Global Superpowers exercise their first-strike capability and turn the lot of them into a plate of radioactive glass.
b) Beryl has gone soft in the head from millennia of being microwaved by Metallia's radiation; the Generals have gone weak, egotistical, and lazy; the Youma Hordes truely are as pathetic as the shining examples we see in most of Sailor Moon; and Metallia is the only reason why were able to make the Moon Kingdom even twitch an eyebrow. End Result: Youma frappe. Doug could paste the Generals by himself; Beryl is pathetic without Metallia; the Youma are a bunch of very ugly and stupid Crunchies; and Metallia is just an evil energy fetus squalling, "I'd kill you all right now, if my umbiblical cord weren't holding me back!"
Considering that less than a half-dozen disorganized junior-high students in miniskirts managed to wipe out the lot of them, I'd vote for (b). Apparently, evil kills braincells.
3) Beryl wises up, realizes that they're in a world of trouble, and orders everyone to fall back and fort up before the Girlscouts bring the fight to them. Starts firing Generals until she gets some which who can grasp the concept of strategy, then formulates and executes a slower, less detectable plan for gathering energy. Then, once enough energy has been collected, wait for the Senshi to get involved in a massive firefight and hit them when they're weakened.
The trouble here is that there are precious-few canon enemies that tactically-knowledgable Senshi couldn't decimate off-hand. Ail and Ann are Crunchies. The really interesting stuff in the Black Moon saga is temporally displaced, thus likely not relevant. Fiore is a snack, but the Senshi will be fairly weakened after the exciting atmospheric deceleration run. The Tomoe-Witches 5 connection would be noticed and neutralized before Pharoah 90 becomes a pressing issue. The Princess Snow Kaguya issue becomes a light workout. The Supers arc is a cakewalk. The Supers movie occurs Elsewhere; likewise, a non-issue. Galaxia, on the other hand, would probably still kick some ass before keeling over.
Either of the possibilities described here implies that Doug remains stranded for at least two to five years. Not good.
To speed things up, we have to go further afield: either Create Your Own Villan (gag) or extrapolate ways to up the difficulty with the canon cast. I'll try my hand at the latter.
The main cast of the Dark Kingdom reads:
1) Youma. I think we can write them off, right off. They're cannon fodder, and not terribly good cannon fodder at that. I'd rank them a bit below drunken circus midgets in combat effectiveness -- at least the circus midgets can conveniently punch their opponent in the crotch.
2) Generals. Apparently, they're running on a considerably-lightened load between the ears, as their grasp of strategic concepts sucks, royally. The incredibly-hokey schemes they come up with just boggle the mind.
3) Beryl. A spoiled princess who was hot for Endymion, then was offered power by Metallia to destroy the Moon Kingdom so she could have him. Does this not just scream "Dupe"?
4) Metallia. The only reason this bunch of flunkies could even knock of a 7-11, let alone an entire magic-empowered kingdom. A free-floating, ludicrously-powerful, non-corporeal being or energy construct (or somesuch) which, for no known reason, wanted to knock off the major superpower of Good in our solar system. This makes Metallia a possible failed first herald for...
x) Pharoah 90. You want to give Pluto a real reason to off Doug? How about the fact that his actions bring about the summoning of nine(ty) kinds of nasty two years before the Senshi should be ready for it?
A big question here is the current disposition of the canon S-season crew. If I recall correctly, Pharoah 90 drafts the Tomoes into his service about two years before the middle of S season, which would be somewhere around when Nephrite gets offed. God knows when the Witches 5 were recruited, but we can arbitrarily say "later", as the Good Guys will have quite enough on their plate, thank you. The status of Mistress 9 would depend on what you want to do with her -- either awaken her and have Metallia waste resources competing with her to summon Pharoah 90 or easily neutralize her a good two years before her prime.
On the Good Guy's side, Uranus and Neptune are awakened shortly after Pharoah 90 gets its hands on the Tomoes, whereas Pluto apparently awoke a couple years before. If Doug is real observant-like and notices reports of Senshi sightings and "Youma" killings where he knows the Inner Senshi haven't been, he might be able to find and subvert Uranus and Neptune before they're battle-hardened and -- more importantly -- before Pluto has had a chance to seriously poison them against the Inners. Whether or not he can get Saturn is entirely dependant on 1) what you want to do with Mistress 9 and 2) whether a ten-year-old can handle the power of the Senshi of Death and Rebirth. (There are some very interesting ramifications in that one....) Chibi-moon is, of course, not likely to show.
This finally gives us a situation where the Senshi plus Doug can die in the process of holding off an uncountable horde just long enough for Moon to do her Princess thing and unleash the Holy Hand Grenade that is her Crystal -- plus that odd "Love/Friendship" bonus which always gets added to her attack and defense rolls in critical battles.
And then, we'll see the Reset.
Feel free to use any of this, if it strikes your fancy.
-----[edit]-----
Typos. Blech.
1) Beryl maintains the canon strategy -- in which case it's a walk in the park for the Good Guys, very dull reading for the audience, and probably very dull writing for the author. ^^ Bonus for the fact that the Reset wouldn't occur.
2) Beryl whips her Generals in line and throws everything she has at the Senshi -- in which case one of two things happens:
a) Beryl has still got it after all those years; the Generals are Generals because they can actually lead; the Youma Hordes number large enough to actually be considered Hordes; and they've all got a can of whoopass to open even without Metallia supplying them with more. End Result: Senshi + Doug are mowed down; Japan is established as a Dark Kingdom beach head; the Global Superpowers exercise their first-strike capability and turn the lot of them into a plate of radioactive glass.
b) Beryl has gone soft in the head from millennia of being microwaved by Metallia's radiation; the Generals have gone weak, egotistical, and lazy; the Youma Hordes truely are as pathetic as the shining examples we see in most of Sailor Moon; and Metallia is the only reason why were able to make the Moon Kingdom even twitch an eyebrow. End Result: Youma frappe. Doug could paste the Generals by himself; Beryl is pathetic without Metallia; the Youma are a bunch of very ugly and stupid Crunchies; and Metallia is just an evil energy fetus squalling, "I'd kill you all right now, if my umbiblical cord weren't holding me back!"
Considering that less than a half-dozen disorganized junior-high students in miniskirts managed to wipe out the lot of them, I'd vote for (b). Apparently, evil kills braincells.
3) Beryl wises up, realizes that they're in a world of trouble, and orders everyone to fall back and fort up before the Girlscouts bring the fight to them. Starts firing Generals until she gets some which who can grasp the concept of strategy, then formulates and executes a slower, less detectable plan for gathering energy. Then, once enough energy has been collected, wait for the Senshi to get involved in a massive firefight and hit them when they're weakened.
The trouble here is that there are precious-few canon enemies that tactically-knowledgable Senshi couldn't decimate off-hand. Ail and Ann are Crunchies. The really interesting stuff in the Black Moon saga is temporally displaced, thus likely not relevant. Fiore is a snack, but the Senshi will be fairly weakened after the exciting atmospheric deceleration run. The Tomoe-Witches 5 connection would be noticed and neutralized before Pharoah 90 becomes a pressing issue. The Princess Snow Kaguya issue becomes a light workout. The Supers arc is a cakewalk. The Supers movie occurs Elsewhere; likewise, a non-issue. Galaxia, on the other hand, would probably still kick some ass before keeling over.
Either of the possibilities described here implies that Doug remains stranded for at least two to five years. Not good.
To speed things up, we have to go further afield: either Create Your Own Villan (gag) or extrapolate ways to up the difficulty with the canon cast. I'll try my hand at the latter.
The main cast of the Dark Kingdom reads:
1) Youma. I think we can write them off, right off. They're cannon fodder, and not terribly good cannon fodder at that. I'd rank them a bit below drunken circus midgets in combat effectiveness -- at least the circus midgets can conveniently punch their opponent in the crotch.
2) Generals. Apparently, they're running on a considerably-lightened load between the ears, as their grasp of strategic concepts sucks, royally. The incredibly-hokey schemes they come up with just boggle the mind.
3) Beryl. A spoiled princess who was hot for Endymion, then was offered power by Metallia to destroy the Moon Kingdom so she could have him. Does this not just scream "Dupe"?
4) Metallia. The only reason this bunch of flunkies could even knock of a 7-11, let alone an entire magic-empowered kingdom. A free-floating, ludicrously-powerful, non-corporeal being or energy construct (or somesuch) which, for no known reason, wanted to knock off the major superpower of Good in our solar system. This makes Metallia a possible failed first herald for...
x) Pharoah 90. You want to give Pluto a real reason to off Doug? How about the fact that his actions bring about the summoning of nine(ty) kinds of nasty two years before the Senshi should be ready for it?
A big question here is the current disposition of the canon S-season crew. If I recall correctly, Pharoah 90 drafts the Tomoes into his service about two years before the middle of S season, which would be somewhere around when Nephrite gets offed. God knows when the Witches 5 were recruited, but we can arbitrarily say "later", as the Good Guys will have quite enough on their plate, thank you. The status of Mistress 9 would depend on what you want to do with her -- either awaken her and have Metallia waste resources competing with her to summon Pharoah 90 or easily neutralize her a good two years before her prime.
On the Good Guy's side, Uranus and Neptune are awakened shortly after Pharoah 90 gets its hands on the Tomoes, whereas Pluto apparently awoke a couple years before. If Doug is real observant-like and notices reports of Senshi sightings and "Youma" killings where he knows the Inner Senshi haven't been, he might be able to find and subvert Uranus and Neptune before they're battle-hardened and -- more importantly -- before Pluto has had a chance to seriously poison them against the Inners. Whether or not he can get Saturn is entirely dependant on 1) what you want to do with Mistress 9 and 2) whether a ten-year-old can handle the power of the Senshi of Death and Rebirth. (There are some very interesting ramifications in that one....) Chibi-moon is, of course, not likely to show.
This finally gives us a situation where the Senshi plus Doug can die in the process of holding off an uncountable horde just long enough for Moon to do her Princess thing and unleash the Holy Hand Grenade that is her Crystal -- plus that odd "Love/Friendship" bonus which always gets added to her attack and defense rolls in critical battles.
And then, we'll see the Reset.
Feel free to use any of this, if it strikes your fancy.
-----[edit]-----
Typos. Blech.