You also do not tell us what you are driving and/or towing. This is important as you need to use a GPS or map system that will not allow you to go under a "bridge too short"! If you are driving a typical motorhome like mine which is 12' tall, you do not want to go under a bridge which is only 11' high.
There are GPS systems which are specifically made for RVs which enable you to set your rig's height, width, weight, and number of propane tanks. It will route you away from things which could cause problems, such as the following infamous bridge:
11 FOOT 8 - The Canopener Bridge . (They recently raised the bridge an additional 8" but it doesn't seem to help much.)
Also, are you going to visit only one campground or taking a much longer trip? If you have something like a popup trailer or a teardrop, you can probably manage with any GPS system.