A truckers map is a good map but not a primary map, As stated the skyline drive and Trace are not on they map because only service trucks are allowed on those roads. I recommend a truckers map because if a truck and trailer can do it most chances are you and your trailer can do it.
The next essential map is a Rand McNally road atlas, it has all 50 states and Canada bound in one spot.
A state map from the first visitors center you stop at will give you major county and state road with a better picture of the road than rand.
I would stay away from Next Exit. If you can read the highway signage you do not need next exit. By the time you get it, the book is normally outdated because hotels (which you do not need), food chains and gas stations change monthly and your book was published last year if you are lucky.