DirecTV does offer internet via Satellite called Wildblue. This is a KA Band dish and requires a trained technician to install it. It requires a analog meter and APA to tune it in. Because it is a KA band dish, it must be mounted in a secure location - a trimast will NOT work. A pole will have to be used - Wildblue will not agree with any non-pin mount installation put on the ground because of a required 5 foot minimum the dish must be located off the ground. Also, wildblue does offer a temporary shut off in service for a small fee - I believe it's up to 6 months you can have temporary disconnect of service. Also, anytime this thing is moved then reused, they will require a certified technician to come out and tune it in for you. If they find out the customer touched the dish, they will remove any warranty on the equipment. Hughesnet is the same way - however, they do offer motorized computer controlled systems that can be mounted on the roof of your RV. It's a motosat type system - with a Winegard computer controller that can deploy and lock onto the satellite on it's own. These are expensive systems, though.
Sources: Certified Wildblue and Hughesnet technician.