Originally Posted by Agent Aero
Yeah you can return to the mojave. I'm sure with all the dlc's once you complete the final main quest you're given the option to return. Or if you want you can hang around for a little longer.
Personally, i didn't like many of the the dlc's. Honest Hearts was my favourite though.
I am not sure but I think the only one you can't return to is the dead money one after you finish it...