So affordable, usable everywhere, Verizon, and stream a movie. Better chances of finding an honest politician.
I would not be the least bit surprised if the Mobely deal had a lot of fine print to it, even more so if you were not ditching your verizon phones and going to at&t (or not getting a direct tv subscription).
If you want to stream a few movies with a cellular plan you need an unlimited plan and need to live in a city that gets good bandwidth. Netflix 1080p movie is 1gb pr hour so 2gb a typical movie. That means you need 3-5mbps constant speed which can be difficult to obtain outside of large metropolitan areas.
If you stay in a single RV park for the bulk of your time then my advice would be to get service from a local...