If carrying dogs inside the vehicle, make sure there is adequate ventilation. Air conditioning is wonderful, but consider what you will do if it quits working. I do not like loose dogs inside, but if it works for you, great. Sudden stops can create a problem for you and the dogs. I have been using portable soft-sided crates that allow me to put 2 big dogs in the back seat of my truck. When I leave the dogs for ANY reason in the car, I have windows open and try to park out of the sun. Temps can rise to dangerous levels quickly even with no sunshine.
If you are travelling for more than a few hours, remember that dogs need a potty and stretch break too. We stop approximately every 4 hours to stretch and pee, we offer the dogs water as well...No food however,since we have a few dogs that get a bit car sick. These are just a few essentials! Make your own list and keep it handy to check off BEFORE you leave. I just hate driving around looking to buy stuff I forgot.
List of stuff to pack:
Shot record. Carry shot records with you any time you leave your property with your dogs.
Poop scoop & baggies. This is my personal pet peeve. Pick up after your dogs when they are out in public.
Water & bowls
Dog treats & Dog food
Leash, harnesses & lines