Originally Posted by quiltmouse
You travel in the car with the cat in the carrier. You stop & let the cat relieve itself in the greens at travel stops. Use a leash. In the motel, put familiar bed, food/water bowls, litter box in the bathroom, with the cat loose in the bathroom.
I suggest a drive of 30 min to "test" the cat. If it never calms down, get a tranquilizer from the vet. (Valium or whatever.)
Don't use just a collar and leash, you need a harness style
restraining system. A cat can squirm out of anything. Concider putting a tag on the harness just like a dog tag, with name and number of your vet. Never take the harness off for the few days you are traveling. crate it when driving. let it out in the motel room so it can use the litter but always crate it before opening the outside door. Remember it is only for a few days and you will have your nerves tested. The more restraints you can keep on the cat the more relaxed you can be.
It may be a good idea to talk to some people who travel to cat shows and find out how they do it. Good luck and happy reunion for the cat and your son. Let us know how it goes!
jrhboxers has very good advice!