Amanda and Dutch are correct. Once you're outside of your home local spotbeam, you won't get local programming via a dish antenna. Your home receiver, if there is one, will continue to receive the local programs until you call or contact Dish and have your locals changed.
If you change your "locals", say you're in San Antonio, and your home receiver is in Seattle. Then you will get San Antonio locals on your RV dish, and your Seattle receiver will not get any local programs until you call Dish back and change your service address back to Seattle.
You can use Dish Anywhere to "stream" programs from Dish to your RV "IF" you can afford a service plan with enough data. Streaming r eally eats up data.
One other option is to have Dish Slingbox on your home receiver and then you can pull off programs from your home receiver and stream that programming via wifi. But it takes a pretty fast connection at your home, and at your RV.