Traveling cross country I've used a combination of things:
A Tom-Tom plus Google maps plus the (available at CW) the RV(or Good Sam Road Atlas map book). When I stop each nite,(using the excellent GS "Travel Guide" campground listings) I open the laptop and map book and figure out the next days' run. ((Our "normal" travel day is 300-400 miles using the Interstates)))
I don't use the Tom-Tom anymore...and never used or purchased a Garmin or similar GPS. I find my cell phone GPS is completely satisfactory and might even be better than Tom-Tom or Garmin or others. Updated quite often? More than the others?
Now...for SPECIFIC information...like overpass heights, something else might be needed (like a truckers book)but that is completely up to you.
