Where we do most of our RVing here in the four corner states it is impossible other than in major cities to rely on cell service to deliver the HD programs we want to watch. We would always purchase (or had one laying around) the same sat. antenna we had mounted at home whether it was Dish or Direct TV, made a stand and set it up upon arrival.
Directv was easy, took a couple of minutes to dial in. Dish takes longer waiting for the receiver to respond, 10 minutes to get the programming to download. Pretty easy, been doing it for a couple of decades, never using anything but compass and receiver after plumbing mast. Total cost would be zero when using old antenna and homemade stand, $50 for new antenna.
We recently picked up a gently used rig and owner threw in both King Pro Directv and Dish automated domes, installed Dish dome on roof using special mount that allows for quick removal. Works OK, slower access to channels as dome antenna must move to corresponding satellite, has 1 HD and 1 SD output, roughly $400. Still carry residential sat. antenna and tripod just in case.