I purchased a portable propane fire place and carry a 20# extra propane tank with me. It makes a great fire, and you can make smores with it. It doesn't create a smoke cloud which keeps your clothes and RV from stinking. And since it's treated like a grill, you can usually use it in your site even if campfires are prohibited. And if you have neighbors in the site next to you, they'll appreciate the lack of smoke.
I can burn it on high for about 12-14 hours on 20# of propane. If you purchase firewood, it will cost much more than that to have a fire for 12-14 hours. Here's a link to the one I purchased:
Propane Fire Pit