I drove from WV to MT this last December, and brought 6 balls with me. I got an RB sweaterbox rack for the trip, and it fit in the car perfectly (Honda CRV).

I didn't feed the snakes for two weeks prior to the move, to make sure everyone was good and empty.

During the day while I was driving, I put a tub divider into one tub, bagged the snakes in cloth shipping bags, and placed each into an upside down hide box so they couldn't move around too much. Three on each side of the divider. I took several shipping heat packs, activated them, then wrapped them in newspaper and tucked them into the tub with the animals. (not touching them though.) The other 3 tubs in the rack were used as storage.

At night when we stopped, the rack was very easy to just lift out of the car and onto my little dolly. I'd wheel it in to the hotel room first. (did I mention it was mid-december and freezing outside? lol) Once I got the unpacking done, I'd pull everything out of the rack, plug it in, and then set up each tub for the snakes. Next morning, bag them up and start over.

It sounds like a lot of work, but it actually went quite fast, and the snakes got to relax each evening. I probably could have just left them bagged for the entire trip, but it took four days, and I wanted them to be able to stretch out and have some real heat.

Within a week of getting here, everyone ate with no hesitation.

Since it was handy, here's a picture of the rack in my car that I took while I was doing a trial run to make sure everything would fit.

It really took up very little space, and since I could use the free tubs for storage while the snakes were bagged up I really didn't give up much.

Good luck, no matter which route you decide to go with.