I agree with Dennis, at least have some plans in busier places. Cold calling and getting a site for one, possibly two RV's isn't too bad, but trying to find a campground with four sites may be more problematic.
Here are some other things to consider. If you don't have radios, Costco sells the Motorola family radios in a two pack. What's nice about these are that they are rechargeable via USB port. You could buy two sets and share.
Second, I would sit down and have a discussion about speed. Last year we drove with a group of four that we normally all meet up with at the campground. This time, we drove together and didn't realize one of the guy's, who took the lead, doesn't like to be behind trucks. He was doing close to 70 and changing lanes every couple of miles. I was the last in line and it was problematic.
Does everyone have the same type of rig and can go the same distance on fuel....we like to fuel up at the end of the day and be ready to go in the AM.
Another issue that arises when the rigs are different sizes, someone often gets a******site when booking four campsites. We travel with friends in a fifth wheel and they usually get the pull through site, even though I'm towing a car. Often the pull thru sites are nicer. Maybe have a plan to take turns in the nicer sites. Even though you're good friends, several weeks on the road will cause some issues.
My point, I would get together before you go and get a consensus of how everyone likes to travel.