We have one DTV receiver for home and on the road. Our MH roof top dish is a compatible dish so moving the receiver is plug and play.
For both DTV and Dish the national programs (CBS, NBC, etc) are spot beam broadcast as locals. That means when you drive to another service address you will still get CBS but that area may not broadcast your games because perhaps they broadcast their local game. In other words you may/may not be able to watch your local Saturday football game. But all of the other channels like ESPN etc are not spot beamed so you can watch them wherever you travel.
Our receiver is also a DVR so all of the recorded shows stay on the receiver.
We watch very little live shows. Instead we watch a recorded 60 minute show in about 30 minutes. So if our roof dish is blocked no big deal as we watch recorded shows or GASP read a book, etc. Our HR44 receiver can record/display 5 HD shows at once so we never have any recording conflicts or lack of shows to watch.
For your multiple rig TVs: With a HDMI receiver output you can split it to multiple TVs. Instead of running HDMI cables you can use a pair of converters to convert a splitter output to coax and back to HDMI at the remote TV. We have this setup at home for the kitchen HD TV. But important point: You need to be able to get the receiver output to the HDMI or coax to the remote TVs. Your rig may/may not be set up in this manner. That can always be solved with additional wiring.