Interesting calculation, moman. I penciled out the same kind of numbers years ago to figure how the cost of an RV stacks up to a motel. Like you, I focused on operating costs (gas and site fees) and found that, for the same money, I could drive around in a mid-sized car or SUV and stay in comfortable motels.

The analysis is made complex by the fact that some things are hard to quantify financially. My primary reason for travel is to visit the outdoors. Staying in a park, versus in a motel some distance away, is an intangible that has value. I'm willing to camp in a tent as an alternative, though I worry that as I get older I will be less and less willing to do so. Having that RV would be a way to "have my cake and eat it, too" by having a bed that's in the park.

By the way, how do you figure that tent camping averages $60/night? I visit parks frequently, and I don't think I've ever seen a tent site fee over $20.