The next update is in testing & should be out next week. (Tinkerer asks that it not show up here for 72 hours after that, to give supporters first crack at it.) After that is another Baron/Greyport update, then two Main storyline (Temple vs Tower) to conclude the game. All existing storylines will then be done, or at reasonable stopping points. That should take it to the middle of next year. If there's engine capacity after that there might be some fill-in content and/or popular ideas and requests as extras, but no promises either way.
Tinkerer does this solo (he has someone [paid] to help with animations, and a QA guy before it goes out for testing, but that's it), and he has a full-time job and a family with kids. He may or may not polish PQ once it's "finished." We do not know if he'll begin another project after this one, and if he does whether it would be a continuation, a sequel with a new MC, or something else entirely. (Personally I'd be very interested in a rebuild once it's done, making use of everything he's learned along the way, but that would be a lot of time and effort...)