General Car advice needed

Hi
So I'm moving for my first real job in my field and of course I'm taking my two kitties with me. They've been on long car rides before, but never this long. We're looking at about 5 1/2 - 6 hours of driving.
Typically Chester is laid back enough that if I put him in the front seat he's ok. The problem is his sister. She howls and howls and it gets him going, which causes him to pant and it's not a fun time.
I'm going to get some rescue remedy, as I know that it at least really works on Chester. They have very nice soft cozy carriers as well.

I'm really wondering what the general guidelines for food/water/litter use is. I don't want them to be uncomfortable on the trip. Once they get there it will take about 12 hours before they're completely back to normal. They're pretty good at adjusting, it's just Dynah in the car that I'm concerned about.

As they do for surgery, no food for 12 hours before the travel. Since the drive is "only" six hours, ( I know it sounds like a lot) I would just plan to keep them in the carriers until you get there. Letting them out, and then trying to get them back in, will only cause more stress for them.

Rub some rescue remedy on their little faces right before putting them in their carriers.

As for the yowling, better get some ear plugs.

Good Luck!

PS I have a friend who recently moved 9000 miles. The cats were in their carriers for almost 24 hours, in the baggage area of the airplanes. they survived without any permanent emotional scars!