You can have exactly the same equipment in an RV as in a home. Dish may tell you they don't support installing any of the DVR models in RV's, but that only means they won't install one in an RV, not that you or an independent retailer can't. I suggest buying your equipment from an independent dealer like Solid Signal or even through Amazon rather than pay Dish's higher prices. For an "Outdoor" pay-as-you-go account, I suggest going through
Dish4MyRV.com. They'll directly connect you to the right people at Dish that know what they're doing. Calling Dish customer service directly can be a crap shoot for RV issues. Dish4MyRV also has some reasonably priced package deals on equipment, if you want to go that route.