I have a Garmin c330 mounted in various vehicles and I take it with me on airplanes and rental cars. I turn it on even in the plane and it works, so it should do well in any RV. This amazes some of the first buyers of GPS, they could not get those units to work W/O mounting in in windshield or using the external antenna.
I love the unit, my business makes find new locations on a national scope and getting lost at any time is no fun, but in an RV it just makes the trip much more stress free. If you travel, you need GPS.
2005 HI-LO 22T
2004 GMC XUV