There are several variables that should determine if you want/need a GPS...If you do a good bit of prior planning of the route you will be taking, it will be useful.....not as much map reading. One comment: make it a section by section trip and have the sections less than 50 miles. This is because most of us vary what our original route is and the GPS will try to direct you back to the way you had planned/input. I input the route for old route 66 that i wanted to travel and it did an outstanding job of trying to keep me on track....on mistake was with me making the sections too big.

The only two "extras" that are nice is the "Text to Speech" option and the largest screen you can find.....

There are many fine brands out there.......Garmin is one of those. I chose the TomTom but not the cheapest model........Another plus to the tomtom is that the military (special forces) use it and are pleased but they may have better maps than you and i can buy.......

And added comment is to use it a while before you leave so you will become accustomed to it giving directions and be able to keep your eyes on the road more..............Also have not found a place yet where i did not have coverage (on the road that is---no coverage inside my home).