navagation devices used on trips

I have a large screen nav system in my Hyundai Sonata that works pretty well, but not perfect. I've learned how to understand its faults and work around them. Before that I bought a portable GPS system that has similar faults. We now keep that in the Avalanche for camping trips. I keep paper maps in the truck as a backup and if I want a bigger picture of where I'm going, or to determine side trips while we are away. If I'm going to a new area, I'll do some prep work using Google maps ahead of time to familiarize myself with the major roads, and relationships between areas of interest.

A couple weeks ago I almost threw the GPS away, because it seemed everywhere we went there was a bridge out due to construction, and we were following detour routes all over the place!