A better plan is to establish a RV Account for your motorhome with DirecTV. Have them install a SWM based HD DVR (Genie preferred) in the Living Area, and H25 receivers in the bedroom, kitchen, and outside location. Order the Distant Network Station (DNS) option for all the receivers. DirecTV will install a HD antenna on the ground (if you park at home, they may mount it on the house). Having the DNS option allows you to receive the network stations (ABC, CBS, NBC, FOX, CW, & PBS) anywhere you go in the USA. Once everything is installed and working install a SWM capable Weingard Traveler antenna on the roof of the motorhome. This will drive the receivers when you are on the road.
Now that you have HD reception fully functional in the RV, you can take some of the receivers into the house, hook them to the external antenna, and have DirecTV in your home too.
I am pretty sure the Whole-Home feature requires special cabling between the Genie and the remote receivers and there is no easy way to do that in a RV. That is why you will need the H25 receivers in the non-Living Room locations. The number of receivers you need is obviously dependent on how many TVs you want to service in the RV and/or the house.