We have used De Lorme Streets and Co-Pilot on the lap top. We like to use it on the laptop because the screen is larger than a hand-held or in dash unit. Both programs can be set up with RV criteria as well as other details that help with traveling.
The main thing to remember about using a GPS while traveling in any type of RV is "they are never 100% accurate" so always double check each planned route with a current atlas. If they should ask you to make a turn and it is wrong...it's a bear to try to turn around and reroute yourself once you know what is correct especially in remote/rural regions.
A friend of ours once ended up on a rustic mountain road high centered on a snow drift all because he religiously followed the GPS. We had it once ask us to make a turn into a rancher's pasture! And worst of all it routed us through an old single lane railroad underpass that was 8' wide and 8' high yet it wanted us to go through...guess they missed cataloging that one!
But, on the other hand on occasion they can be a handy tool.