This is a topic of great interest to me. DW and I (and various animals) spend 6 months in FL and 6 months in IN, and we have DirecTV dishes in both locations, carrying the just the boxes back and forth. When we camp it is always in SP CGs, so no Wi-Fi. I bought a dish and tripod from TV4RV
and it is relatively (30-45 min, not worth the trouble for a one night stay) easy to set up.
The major problem, especially in the Northern US, is the tree cover in SP CGs, it is hit or miss if you will have a clear view in the direction you need. I would say about 65% of the time you will have success.
It is worth it to us, especially on longer trips with stays of 4-5 days in each CG. We also bring a Verizon 4G hotspot for internet access for tablets and phones, but watching video with that will burn through GBs of data pretty quick and they ain't cheap.