I had the exact same situation, I sleep for 8+ hours which is almost guaranteed to make it crash. Sometimes if you sleep or wait in interiors, it's fine until you go outside, or sometimes if you wait outside, upon loading all assets back, it crashes too. At first I thought it might be EFF and the fact that my pc could barely handle 3 followers, which might also be the cause, however I found that it wasn't actually that mod that was causing it
This problem also happened to me when I became thane of whiterun and when I already had uthgerd, a mercenary, and had just recently picked up lydia. I don't know what to tell you dude. I just installed 4.4 yesterday and I'm dreading things like what you're saying and that it will happen to me again. Good luck though, and please let us know if you find a solution!