There are companies that run you up and back, or at least in a loop. Some companies have a strong local/regional customer base, That's generally how I run my own truck for my company, due to the fact that our rate structure didn't collapse during this recession the way most of the "big dogs" did. When you're talking about a large difference in revenus between taking care of my own customers vs. a partnership with a big carrier, it doesn't make sense to stay out and bounce around.
But I have no limits on the distance. We will run all 48.