About the save file, I make sure to keep the npc numbers low by deleting most of the "not in world" families and deleting most of the elders so that I won't end up with 50 ghosts wandering around town with seemingly no way to release them to the netherworld.
Other then that then I haven't had any problems so far, I do save a copy of each generation in my library just in case something happens though.
It's too bad the family tree gets culled every now and then though, one day I'll take a look at it and there's no grandma/grandpa on there anymore. ):