I have the same problem, and putting no strays sign worked for me for a moment... until it started crashing from the mail delivery girl coming to my lot :( I feel so disappointed that it crashes so much
Another possible fix for some other crashes is to turn sim voices in the options. I think the option is called vox and should be in the sound settings somewhere. It's the last one anyway, just turn the bar all the way down. There are some reports it helping. I did it after my game crashed again and it didn't crash since, but I haven't played a lot after that.
Though if it specifically happens when the mail delivery girl comes, it might not be related to sim voices at all. I'm sorry to say I haven't encountered a fix for that yet. Hopefully EA patches it soon.
