RPMs were pretty high initially with the 30" tires. 70 mph was about its top speed- at least comfortably. But now with the 33s, I'm equivalent to the factory option 4.10 gear ratio and stock tires (or real close). I don't really know what the RPMs are, but I can run 75-80 and get 16 mpg while doing it.
I used to live in Wichita, KS- I know what you mean. We never camped while we lived there.