My campaign has been running for a few years now (the players and PCs have changed, but I still consider it the same campaign. At first, we ran The Night Below mega-module in 2e, then continued that campaign into various one-shot adventures with no modules ("winging it" as I call it). After college, I updated the setting from Forgotten Realms to Golarion, placing the town (now a metropolis) of Haranshire a little bit north of Sandpoint in Varisia, since the group rarely left the Underdark into the Realms proper anyway. So I had my new party introduced into the world at level 12 ( a choice I now regret) and picked buts and pieces of the first 5 books of Second Darkness. My party really enjoyed Second Darkness, even though they technically failed (the five focus glyphs were destroyed but Allevrah still dropped the star on Kyonin. For fear of another attempt, the Elves of Golarion went into mass exodus back to their original home planet, Castrovel. I effectively removed all elven settlements from my game world, replacing them with either Drow beneath the surface or something else entirely. After a few more "winging" games, I needed a new module for the party and the demonic influence of the Moonscar intrigued me. Again, the party loved it, but now the module is over and my party is level 18/19 and I want to retire the characters. I have a very rough plan of what I want to do from here with lower level characters, but I don't want to push the party too hard. I plan to have the party return to the moon and cover some of the places not covered in the Moonscar. Distant Worlds is my new bible for the campaign essentially. After the moon, the party will find gates to the two nearest planets, Castrovel and Akiton. I plan to write up a few new gates to the other inner planets, then finally grant the party a method of space travel (around level 10/11 maybe?) such as Shantak mounts or something. I hope I can make it compelling for the party, but I usually find myself too hung up on geography and creatures to write a decent story. I guess the advice I'm looking for (I'm so long-winded lol) is any kind of story hook that will be enjoyable for my three players while still tying into my own personal campaign setting. Here's the only rough ideas I have;
1) Allevrah from Second Darkness is still alive and working with the party (sort of). She can't be trusted, but they are allied in some sense. I could easily have her betray them, but I'm not sure how
2) The Rockseer elves from Night Below left the world during the course of the module and I later used them as a hook when I had Allevrah kill them off and steal their secrets. I could have them return to Golarion, or even better, on one of the other planets, maybe even Castrovel with the elves or lamashtu.
3) I want to introduce Psionics since Night Below was centered around savant aboleth and that one intellectual property with the tentacled faces ;) I wanted to wait until PFRPG added official psionics rules, but I somehow doubt that will even happen because of balance issues. I would use Psionics Unleashed I think, but I am clueless as to how I can tie these rules into a current game. This is only minor, since I would probably only allow NPCs and monsters to access these abilities because I've had too many problems in the past with Psionic characters utterly ruining my game (granted that was 2e, but still I've never been a fan of classes that provide a pool of anything other than spells, ie monk, gunslinger, etc because even at low levels they have a TON of points usually when casters can do maybe two 1st-level spells)
Alright, I don't even know if anyone can offer me suggestions since I've stubbornly listed everything I already have lol, but any ideas would be greatly appreciated