Without a clear definition of the costs included, there is no way to know how good the numbers are. If you don't take into account any of the costs of ownership of the RV, then the numbers appear high, but with everything else in the mix, they could actually be low.
The major cost per day w/out ownership, includes camping fees, food, drink, entertainment, fuel, on road maintenance, etc.. You can come up with a pretty good estimate of that on your own. Most of the time, I average $100 plus or minus a day and that includes all of the above, with some eating out. I've been a lot higher and sometimes lower. I drive a 40' Wanderlodge that averages about 5.5 mpg of diesel.
When we add, maintenance, repairs, modifications, insurance, license fees, tires, original cost, financing, depreciation, taxes, etc. to the mix, then the cost per day is considerably higher.