Need help with a movie title

Ok, it's not really a mainstream movie, but it's definitely not horror so I'm posting it here.  Here's a plot description:

Girl from Boston (I think) leaves home to go on a road trip to see her friend that's going to school in Florida.  When she stops at a rest stop, some guys slash her tires and steal her money so she is stranded there.  An old couple who are driving an RV offer to help her out and let her hitch a ride.  The girl comes to find out that they old couple are making money by the woman prostituting herself out at truck stops.  The girl then decides she wants to give it a shot as well and gets into the business with the couple. (No, this isn't a porno.)  She eventually wants out so she holds up the couple and we come to find out that the money that was stolen from her, she stole from her place of employment.  She calls her friend that she is trying to visit and her friend tells her not to come because the police are looking for her back home.  The old couple help her out and get her out of the business.

And that's pretty much all that happens.  I've only seen it once but I really enjoyed the movie but I have no idea what it is called.

Any help?