Well, I've pulled everything and put it back in, then remembered that the item that stopped working was a custom tree. I put all of my plants in a separate folder and took them out of the downloads, and the game is working better now. I guess my only solution is not to use custom build mode plants anymore.

Now all I have left to do is find out why some of my lots insist on getting "stuck" while loading...
Thank you for the help, Joy! :angel: