No phone service as in cell, land line, Skype or whatever then you cannot change your locals. But you will get the nation wide non local channels.
"So what happens when my system/RV moves about the planet?" You bought equipment for the US and it won't work for most of the planet. It won't even work very far outside of the US borders.
BTW Dish doesn't care what equipment you have. It could be a portable dish, your dish or one of another brand. You tell them your location and they set your account to receive the locals.
GPS is an entirely different technology. It receives multiple timed satellite signals and can compute the location including altitude.
You bought some expensive equipment without understanding what you bought. If you remain unhappy with your purchase then sell it, otherwise enjoy!
