I'm an NRA Certified Instructor, and I shutter at what you posted that your CCW instructor "said".
I routinely travel From Montana to Florida (and back) twice a year. Every state is (at least slightly) different, but understanding where you can legally carry is not that hard of a task. This site has a good "reciprocity map", and two other good site for other information on vehicle carry, open carry, etc. are http://www.nraila.org/GunLaws/ and http://www.handgunlaw.us. Depending on what state issued your CCP, you may be quite legal in many other states. Also,there are several states (Florida in particular) that issue permits to non-residents, and many states (all but CO, SC, MI & NH) honor non-resident permits.
But here's a tip on the fastest way to lose your CWP, and probably your right to even purchase a firearm... Get convicted of carrying a concealed firearm in a state that does not honor any of your permits, or get convicted of a "carry violation" (carrying in a prohibited place) even in a state that does honor your permit.
But here's another suggestion... If you know where the "Bad Truck Stops" are, avoid them! I realize that you may have a lot of constraints on going a different route, but you may be able to pick where along your route that you stop.
So think about this one... Prison is Prison, and in some places illegally carrying or possessing a firearm - concealed or otherwise - will allow you to become intimately familiar with the inside of some State's Pen!
StaySafe
MG
NRA Certified Instructor - StaySafe(tm) Training
Pipe Hitters Union, Local 417
Join the NRA! The Gun you save may be YOUR OWN!