RV GPS Recommendation

I just use the standard auto GPSr with a box of paper maps as back up.

I have a Rand McNally 7730 with a 7 inch screen. The length, height, and weight for the RV or RV plus tow or towed vehicle can be set. The GPS will then route you away from low tunnels and bridges. It can be set to avoid small roads and dirt roads. There are lots of other settings for warnings about going over the speed limit, approaching sharp curves, construction zones, etc. I travel by myself; the cat is no good about reading maps and gets bored with the smart phone or tablet, so I appreciate the step by step directions and the visual showing which lane to get in for exits and interchanges. Also the motor home speedometer is hard to see it some lighting so I find myself using the GPS speed indicator – much easier to see. I am very happy with this GPS and now that I am used to it, I find it easier to use than the Garmin in my car. There is a learning curve though, it takes a while.

Google Maps on your phone! It's the only up-to-date mapping program around. You likely have already planned where you want to go before you leave so the GPS is best served by simply getting you there.
This is, of course, completely my opinion. I do use one of the latest 7" Garmin's in my coach but I bought it years ago. I will never buy another GPS and I use my phone to get me the last few miles to the campground to ensure accuracy.