OK. I seem to have found a couple of things that help:

1) "save" your game often by going to the Launcher
2)when you exit the game for a while, go to the Laucher first, don't just turn off the unit from the game screen
3)don't leave it on "fast" overnight
4)don't attempt to play the game while it is on the charger because you're so addicted that you want to continue playing it even after you've completely run out the battery AGAIN!

Going on three days without a crash or freeze, which is the most since I got the game.