Sounds like fun!!
We went camping last September at Yellowstone NP. It was below freezing every night. We would wake to a frost layer on our tent.
We have a down-filled puffy coat for Quasar that he wore most of the time and always at night.
We use an air mattress that has never been damaged by Q. We zip two sleeping bags together. Q is loose inside the tent. There is a little box at the foot of our mattress. We also leave his cat carrier open in the tent with a small fleece pad in it.
Usually, he waits until we have settled down then comes and lies on top of our sleeping bags, between us. Last year, with the frost, he finally got inside the sleeping bags with us on the last night.
We feed him alone inside the tent a few times during the day. We can't leave the dish out for him though, or else our dog will eat his food.
We also have a pop up portable kennel that we put him in when are unable to hold him on his leash. We have been using the kennel since we first started camping with him at about 4 months of age so he is used to it. I am sure he could rip a hole in the nylon walls if he tried but he doesn't know that!
Make sure to include your kitties in your daily outings or else they will be bored when you return to your campsite and probably keep you up all night.
Also, N.P.s don't allow you to leave a pet unattended for the pet's own safety. Make sure you have a very secure harness and a retractable leash is a lot of fun, allowing kitty to explore but still remain within a safe distance of you.
Where are you going camping?
Let us know how it goes.
Stay warm.