I know it autosaves, but i want to make sure that if I turn it off, I'll be able to come right back to where I left off. I don't want to go to a safehouse every time I'm done playing. I just finished a mission... can i turn off the PS3? Thanks!
You can always do a quicksave from the phone when you're not in a mission.
As for autosaves after missions... I dunno! I want to know myself but I'm too scared to risk it.