I would definitely not put them in the cargo.
Driving is super easy-I’ve done 12 hours of driving and I can certainly give you tips
Especially since you guys are in summer and thats when you worry.
To be honest its easy to travel with them-they get right used to the car moving and it’s not big deal after a few clicks
1) Bring syringes to force feed water if they aren’t eating-(also bring critical care in case, or mashed pellets)
2) Sweeten your water with apple juice to encourage drinking, and bring water from home so it tastes the same
3) You can tape up sheets or pillow cases in the back windows to keep the sun from streaming in-if you don’t have air conditioning in your car-follow all the BB cooling tips seen here: https://binkybunny.com/BUNNYINFO/CoolingTips/tabid/123/Default.aspx
4) NEVER leave them in the car to go into a resturaunt or for a break-unless you have a car starter so you can run the car while your inside-don’t leave them in. People always underestimate the heat or overestimate the time it would take and bad things happen so don’t chance it. Get your meals drive thru and use the ladies room quickly
5) Bring lots of veggies and make sure you have their favorites on hand. Not only will this encrorage them to eat but also keep them hydrated
Also what I did-and you maybe can’t-depending on how much stuff you need to pack into your car, was I folded one of the rear seats down so the trunk was accessible from the back seat. So they had the trunk and the back seat to run around in. Rupert made himself a tunnel in between suitcases and enjoyed himself. I used 1/2 a carrier as a litter box and they sort of used that -little bit of poops elsewhere.