I guess I'm not aware of all the things that I need to know about the routes we plan like grades and tunnels and all that. we have two Garmin GPS's, one is a Nuvi 2555LMT the other is a Nuvi 65 LM, 4" and 6" screens respectfully.
Both were reconditioned and one was $113 and the other about $95.
Both have good screens and of course the 6" is easier to see but I use the 4" and the navigator uses the 6". Oh yeah, they supplement good AAA paper maps.
We have been to all 49 continental states and all but three Canadian Provinces. Never had a problem but a $300 or $400 dollar RV specific GPS may work better.