I'm thinking of leaving Wellspring, can and will I be able to return at some point?

During the campaign of Rage you eventually are given the opportunity to leave Wellspring and the Wasteland to a different location (hopefully this isn't a spoiler). The character you are talking to mentions to finish anything up before leaving. Do they mean I will have absolutely no chance to come back to Wellspring at a later point?

I'd like to continue on with the story, but at the same time there are some achievements that I'd like to finish up. As far as I know the only ability to complete those achievements is based on specific characters that reside only in Wellpsring or the surrounding area.

Solution 1:

From an xbox forum:

Yes, just talk to the guy by the "blimp" in the underground portion of Subway Town and you can go back as many times as you would like.

Solution 2:

When the NPCs start talking about Capital Prime in Subway, make sure you are done with racing in that campaign because the Authority will shutdown the basement raceway.