What If the bottomless pit sent dipper,mabel,stan and soos to another dimension?
It would be interesting if they end up in the same dimension that ford is and there will be a lot of interdimensional shenanigans such as the mabel dimension full of mabels,alternate realities(reverse falls,monster falls...),alien realities(maybe once mentioned in journal 3) and many and hints of other shows such as rick and morty(later it is reveals that bill was influencing the bottomless pit hence why the gang got lost in the multiverse).
I would also like to think that their disappearance would cause wendy to try to find them only to stumble upon the underground portal in mystery shack and accidentally send herself across the the multiverse and it would kinda be like the whole marcy thing from amphibia as wendy would absolutely love traveling between dimensions and bill will use that to manipulate her since she doesn't know about bill yet while we get to see wendy get the depth she lacked in the show,subsequently at the end of season 1 the gang manage to return to their home dimension only for wendy to suddenly being shot by bill's blue blast leaving a hole in her before reaching the portal to her and the gang's(specially dipper's) horror while bill cackling and mockingly say "now look what you made me to do red!" thinking that she died.
When they return they see gideon taking over the shack,gideon try to be his obsessively creepy self but mabel being in grief she attacks him with rage and sorrow to everyone and gideon's shock,the gang had to stop mabel before doing any serious harm to gideon who was left completely dumbfounded and scared.
There are some few changes in season 2 such as ford running for candidacy and successeding in it,manly dan and his boys mourns wendy's apparent death and in one scene we see dan actually shedding tears,northwest mansion episode the northwests try to use the town's collective grief to gain credibility by making an expensive funeral for wendy only for the lumberjack ghost who is reveals to be the ancestor of wendy to lash out in rage(the rest of the episode is almost same as the show),robbie and dipper reconcile through their grief in losing wendy so as wendy's teenage gang and robbie apologize for bullying dipper and no roadside attraction(good riddance!).
In later episodes of season 2 it is revealed that she indeed survived when bill taunts dipper in his dream,in one episode dipper,soos,mabel and stan secretly activate the portal to get wendy back to ford's dismay as ford was against this action leading into her return but to their terror wendy has been brainwashed and mutated into something like an eldritch demon with bat like wings,multiple small eyes in a place were her left eye suppose to be,claws,scarlet texture and can shot freezing breath from her mouth.later she flees and attacks her teenage gang and nearly brutally kills robbie,she doesn't successes but robbie is traumatized for life(because I hate robbie).
Weirdmaggedon starts by the corrupt wendy as she baits dipper and mabel in thinking that she indeed cured thus they get imprisoned in a bubble in which their worst nightmares manifest while corrupt wendy and bill simultaneously cackling mad. stan and ford reconcile and they and soos go to save the younger twins before dipper and mabel lose their sanity,finally at the end dipper managed to reach out to wendy and snap her back by reminding of their bond,her friends and her family by which wendy's memories finally truly returns but she is still in her mutated form and as long as she is in that form the zodiac won't work so she tricks bill in going inside her mind and asking the gang to use the memory eraser which they do while bill begging and one of him and wendy's last moments scenes is like:
Wendy:hey look at me you one eye nacho!you can enslave my mind and body but you made a fatal mistake,you messed with my friends!
Bill:you're making a mistake!I can give you anything!money,fame,riches,infinite power your own galaxy please!
Wendy:no thanks I'm a flipping honorary pines!*then kicking bill to the oblivion*
Due to bill no longer be alive weirdmaggedon stops like the show and wendy becomes human again but her memory is still blank,fortunately she regains it thanks to dipper showing her her weird teddy bear and the gang helping her,later wendy breaks up with robbie which he is fine with it since he start developing feelings for tambry so as her but unlike the show wendy is neutral inthem being a couple and the end is the same except wendy hugs dipper,thanking him for not giving up on her and say he means a lot to her just like the show except she also tells him he is the coolest person she ever met and she sewed a blue pine tree in her hat before switching it with dipper's.