Seems like that would be the best way to bring him back if they ever decide to do a sequel to the series.
What I actually kind of want is for Dipper and Mabel to return to Gravity Falls, and the now Soos owned Mystery Shack, and to have a bunch of wacky adventures/overarching mysteries there. The Stan twins, meanwhile, are having their own seafaring adventure and only make very brief cameos in a couple of episodes via emails and calls they share with the younger twins.
Then when it gets near the finale, Dipper and Mabel get an ominous, half panicked call from Stanford about Bill has been influencing Stanley's decisions and biding his time in the back of the man's mind. Ford gets cut off midsentence, and the line goes dead silent, only for a really creepy mix between Stan and Bill's laughter to fill the receiver a few seconds later before the call ends entirely.
The finale is the Mystery Shack crew trying to track down the Stans and figure out what happened to them.