So, I recently started getting a crashes with a Level 48 character on an install that has had minimal problems (up until now). It is, admittedly, a pretty heavily modded Skyrim, but there were barely any crashes and zero consistent crashes up until this point.
The problem is as the description states: when a fast-travel somewhere, the game crashes. There's been a few exceptions to this--right now, as far as I can tell, if the game has the location flagged for an active quest (even if the quest isn't active in my journal), it'll cause the game to CTD.
Crashes on fast-travel when:
Going to a bandit camp to complete a radiant quest
Going to a Hold capital to retrieve my reward for a radiant quest
Going to High Hrothgar to talk to the Greybeards about a peace treaty
Doesn't crash on fast travel when:
Going to Whiterun to buy supplies (no active quest locations there)
Going to Markarth to buy supplies/for training (no active question locations there)
Going to Riverwood to buy lumber (no active question locations there)
^ This is all speculative, and I don't know if it's helpful, but I'm just trying to get a sense of what is going on.
I have removed a few mods--I think two or three total. One of them was recent (it was this mod), but I did clean my save with Fallrim Resaver (I removed one unattached script). I do havea lot of non-existent form instances, but apparently some mods need those, and I don't really know how to read them. I don't know if Resaver is fool-proof, but I have a hard time imagining one script would bork my character for all eternity (although I'm not super well-versed here).
I'm on pre-AE Special Edition, so here is my .NET Script Framework Crash log, if that's at all helpful: