More Lots having issues

DJGeoRob​  The size of your save may be part of the issue.  Large saves tend to fall apart eventually, although how long that takes can vary quite a bit.  And I'm not saying that your save is about to be unplayable, only that you should keep an eye out for signs of spreading corruption.  I would also keep backups, and maybe back up your households and any lots you wouldn't want to lose.  If you don't need the backups, great; if you do, you'll be glad you made them.

I would try bulldozing the other two lots in your main save and see what happens.  For the Von Windenburg lot, there isn't an easy way to fix it if it crashes or locks up the game even when you bulldoze it.  But as a test, I'd still suggest saving an almost-blank 64x64 lot and placing it over the current lot, to see whether that lets you exit.