nadsab,
By the way ... you have an excellent RV for the type of camping you prefer!
We use a late model high end five inch Garmin vehicle navigator on the dash of our RV. I say "late model high end" because they do make continual improvements in their line and lower models in their line do have irritating usability negatives because of technology differences. We have had earlier, lesser, models and our latest one really is a breath of fresh air to use. We keep it updated continually and it's solid state memory can hold all of North America plus hundreds of thousands of custom POI's on tap. The particular model we have can now be bought for way less than we paid for it last fall.
That being said, we also use several (an entire book is required for each state) outstanding map books along with the Garmin. These map books show extreme detail, especially outside cities in the countryside for each state - including obscure camp grounds and points of interest. We rockhound a lot in remote places beyond campgrounds - we often camp way out there too - so we use all three on concert ... the Garmin, the map books, and ultra-detailed specialized rockhound map guides.
Other posters above have mentioned that most vehicle navigators probably won't work for pedestrian use due to battery life ... which is true for most models. However, our Garmin vehicle navigator does have a superb instant-on/instant-off sleep feature that extends it's battery life to many days ... supposedly so you can merely switch it on to check you position then switch it back off to proceed when walking/hiking. We haven't used it this way yet, though.
Here's a link to those great map books - like anything worth it's salt they're not inexpensive:
http://www.benchmarkmaps.com/
