In the game I'm planning right now, I know where I want the PCs to end up. There's an evil empire that has served as an insurmountable foe in most of the games I've run in the last 15 years. Usually, the PCs just thwarted one scheme (albeit a major scheme) in each game. Now I want to bring the whole thing down.
The whole thing is, unbeknownst to even most deities, ruled my a mortal risen as a god. The empire uses psionics to great effect, with elite strike teams of psychic warriors (in 2E in was wild talent fighters) trained to teleport (yes, a bent rule) into places, do what the need to, and teleport out. The commander of the military is a psionic Death Knight. The central citadel has outer walls of pure adamantite. Etc. etc.
I want the PCs to hit about 30th level, maybe more, before they finish. Ultimately, that includes taking out a god. I _don't_ want the final assult to be just another adventure, no matter how cool. I want it to be a culmination of what's gone before. The aria of the campaign, and possibly the world as a game setting.
So, how do I have a constant draw in that direction without either:
a) Overwhelming the characters too early. "C'mon, we gotta go get the emperor. Who cares if we're 1st level."
b) Running the group through an obvious set of hoops. "You need the key to open the vault, which contains the piece of the sun, which can be forged into a sword to slay the dragon, who guards the portal to the netherworld, where you can find the throne of Death, who holds a blade that can kill even a god with a single touch."
b1) Running the PCs through said hoops without giving them a chance to breathe. I want there to be some sense of time and the characters not being pressed constantly. I also want to add in plenty of opportunity for side quests.
c) Letting the players feel like they are just practicing until the day they are strong enough to face the emperor.
d) Stringing together a bunch of unrelated stories and throwing in the final assault as just an epic level last hurrah.
I suspect the answer lies next door to b), while avoiding b1). I'm just not sure how to go about it.