Some things I've done......
Store trees and shrubs and deer and fences, not all of them but maybe 5 - 10 at a time and then check the stability. If you spread these things out (except for the fences, natch) you don't really notice them missing.
Close all other apps before opening TSTO. Do this by double clicking your home button (any device) and the bottom task bar will show all the apps open. Click on them so the red minus sign appears and close them. If it asks "are you sure you want to delete?" then you have done something wrong. It should just close it.
Don't collect all at once. If you have timed your stuff so that everything comes due at the same time? It will crash. Spread things out or collect some, synchronize, collect more.
I also assign my characters in batchs.
It has helped.
I added 4 plots of land a couple of days ago and have been crashing fairly consistently, however, the game just needs to catch up to my additions. My game now crashes every 15 minutes or so instead of every couple of minutes.
There are always stability issues with updates, just be patient and hopefully some of the tricks above will help.
Finally, I know some don't want to read long posts (TL;DR which I think is a rude comment, BTW) so don't read it but then also don't whine that it is not working when people offer up advice. Whoooo that was cranky lol...sorry!