In September I'm going up for a day session of the US Open --go Rafa!-- with an old friend who played in the first ever long-running campaign --go AD&D 2nd edition!-- I DM'ed. I've never played in, or run, a game like it since. The last session was approximately 14-15 years ago.
Good luck with that! I'd be interested in how that turns out.
do you have the same players? (else if you have a mix of old and new, keep in mind that the things you do shouldn't be dependent upon the old stuff else the new guys will feel lost)
The only new player is my wife, and all my players from that game are still around. I'm working on some ideas to incorporate her into the game without her being out in left field. It is difficult. If you ever watched Farscape, and you missed an episode, you could become totally lost. It kind of had that kind of feel to it. Plus it's Planescape and if you aren't familiar with that setting already...
I think what I would need to do would be to give her some kind of knowledge that they don't have to make things even. Then, everyone is bringing something to the table and nobody is left out.
For the sake of continuity, (and i can't tell exactly from the way you worded it so i may be misunderstanding) rather than go for a side adventure that they would have had during the campaign, maybe go for what they are called to do after the campaign? allowing them to see how things turned out? (not that you couldn't pull off the side trek flashback thing, just make sure it is isolated enough that what they did there wouldn't have affected the campaign adventures and outcomes that they did do the first time through).
See, the reason I am thinking about doing a side adventure that happened at some point during the campaign is that I don't think I could pull off a full level 20 3.5 game after not having played it for several years. It was incredibly difficult running the game having organically grown into it from them being level 1 rapscallions. I do not want to be fumbling with the rules during the game. Level 13-15 I could probably do.
If I could do an after campaign adventure, though, it would be blow their minds fantastically. It ended on kind of a cliffhanger, at least as far as the fate of the world was concerned, even though their part in the story was over. Exploring what happened as a fallout to their actions could be a great concept for them to explore. I'll think on it some. This would be the big gamble that could pay out incredibly well.
I don't know how fickle your players are, but you may want to be prepared just in case one person wants to change their PC for some reason. so how would you account for the new PC and absence of the old.
Not a problem. They love these characters.
The only thing I'd be worried about is, if using the "side trek" dealy, is that it assumes the PCs survived the side trek. Otherwise...the main campaign plot would not have been able to carry on. Or even if one PC dies, and the others get that PC raised, I have to assume somewhere along the line someone would say "Hey, remember that time you died while we were fighting the the giant slimy Snot Avatar of Gorgolaxicon that was attacking Happyvillage Town?" And then you're stuck retconning. Which is fun for absolutely no one.
I actually gave this some thought. The thing is, though, they died
a lot in that game. We lost count of how many times they died. More would be a drop in the bucket. They even had a kind of TPK insurance set up, where if they disapeared and were presumed dead, there would be True Ressurections for them. Their stuff would be gone, though, and they'd have to get it back.
That brings up another rub with doing something in the middle of the campaign, though. We don't have character sheets of, say, a level 13 party. We'd have to make them up, skills, feats, and magic items worth. That could either be a fun exercise or an inconsistency, depending on how people view it.
More to think about!
I have to agree with [MENTION=807]fba827[/MENTION] and suggest going with a "post-campaign" trek. That lets them be the big damn heroes, you don't have to pull punches, and there's no retconning/handwaving required, keeping everyone happy and not breaking immersion at all.
But, yes, this makes sense, and I agree with it. It's just daunting. I'll have to give it some thought. It's not like I'd have to run the game next week... or next month for that matter. At the earliest, probably October.
We've got one guy in the group that hates time travel because paradoxes make his head hurt. I think he would go frothing mad if any inconsistencies cropped up in the campaign. So, its looking more and more like I need to suck it up and relearn how to run a successful 20th level game!