I too have a lot of CTDs (crash to desktop); sometimes I go days without one, but yesterday it happened 3 times in 5 minutes, everytime I tried to fast travel.
I think I can agree with the saves thing. I deleted a bunch of old saves (I'm not going back that far anyway), went back in, went a distance, saved again, and fast traveled elsewhere eventually, and the game was okay after that.
It would seem to be a "build up" kind of thing with the saves.
For a PC user, that could also be due to hardware issues; insufficient RAM, or, very possibly, too weak of a power supply to handle the GPU. (A good power supply is important!) Or, too many mods/bad mod. None of that pertains to my case however because I upgraded my computer all around, and don't run mods, currently.
Another thing I did was disable Steam sync. With that enabled, I'd have to wait 5-10 minutes before I could launch the game again. Now I just do a sync manually at the end of the night when I'm done.