A very good time to go camping! Though, Yellowstone may be at it’s best in September. Beautiful fall colors, the elk are in rut, much steam from all of the thermal activity, in general the wildlife is more active getting ready for winter. Camping without water will be a bit of a challenge, we feel real good with water onboard to around a -10 F, with our Class C and a -20F with our 5er....but both are designed for cool weather. Fall and winter, truly the magical time to RV.....if you are properly prepared! Be Prepared and Enjoy!
As far as YNP campgrounds. I don’t think that any in the park are open .....though I may be wrong. There are a couple of NF campgrounds outside of the park, on the east side between Wapiti and the park, that remain open!
Gary, I’m envious of your 4WD. We want to convert.....but, are waiting on the winning lottery ticket! ;) About $15K :( memtb