When I was young and used to camp using borrowed tents from the military, I used to take my oven rack and use it! It would fit over any fire ring. It wasn't adjustable, and you had to cook close to the coals/wood, but it worked fine. If you opt for this, but do it more often than I did (a couple times a year) you might toss in a couple of cinder blocks to hold it up.
We were on the road in a trailer for three years straight and mostly used our little smokey joe weber for cooking, fires in the rings for atmosphere and fun. Yes, most places nowadays do not allow fires outside of specified fire rings. People are just too careless, and often do not bother to find out what the fire conditions are where they are camping.
Another hint is that if you're cooking in a pot over a fire, apply a coat of dish detergent to the bottom and sides of the pot. Makes cleaning that black stuff off much easier. I'd just use my regular old kitchen pots (in those days revere ware) and this made the clean up a whiz. I also make a point of bringing any cheap teflon skillets that have seen better times. At the end of the trip, they go into the trash. You can find these so darned cheap that you can consider them disposable.
After three years full-timing on the road, I'm a bastian of information on camping. Just yell if you have a question.
BTW, RVs that have been fitted with a ramp to the doorway can be a real blessing for handicapped individuals and their families. You can hold onto walls and counters to get from room to room. When you are in the hospital for treatment, those hours and hours of waiting are much easier for you and your loved ones when the RV is in the parking lot. Instead of trying to figure out what to do for 4 hours, or what restaurant is handicapped-friendly, or eating truly nasty hospital food, you can go "home", have a sandwich, and take a nap. We made many freinds on the road who had an RV just for that purpose, so they could go to a military installation, VA hospital, or the Mayo. We met people crippled from polio, unable to walk more than a few steps because of heart disease, people undergoing chemo. There was even a woman who had oxygen pumped into her little RV so she could go off of her oxygen tank!