A solution that might work for telltale and for fans would be to have a large map that can be reused from episode to episode, but what's there and where you are able to go might change. A King's Quest game wouldn't have "you can't go there yet" , it would just kill you if you tried to go someplace you shouldn't. Even in the old KQ games there were some areas that became inaccessible over time (falling bridges, sinking boats, etc). Of course, there's also the possibility of the mini-realms from KQVII, which was itself broken into episodic chapters, being a decent route for TT to take.
I finally built a working time machine! It's not perfect yet though, it only moves forward in time and it's a bit slow. You have to be in it for one second for every second you want to go into the future.