I agree with above. If both are on the same account, both the RV and your home receivers will be changed. Of course your home can't actually receive those and if you have the home DVR set to record favorite programs at home you will not get them recorded.
But as for changing locals in the RV it is easy. When you call Dish be sure to say you are in your RV and want to change your service address, not your billing address. After a few minutes, and sometimes a receiver reset, you will get the nearest locals. You do need to give them a valid local address when you call.