My "rogh math" would be something like this
5000 miles in three weeks = 21 days,
5000 miles average 8 mpg 625 gallons
635 gallons $3.80 / gallon = $2,375.00
21 camp ground stays $40.00 / night = $840.00
21 days food, times (3) meals a day average $15.00 a meal = $945.00
Total cost 21 days not including maintenance, insurance, price of the RV, etc. $198.00 a day.
My biggest concern after reading these type of posts since Al Gore invented the internet in the 90's is WHY.
Why do people care how many MPG a vehicle gets or how much it costs to have fun RVing.
Bottom line, you will never ever be able to justify MPG, and the price of Rving, NEVER.
It's just a great fun thing to do with the family and no price can ever be placed on that.
If you offered me one million dollars and said - you can not sit around a campfire deep in the forest with your family eating smores and hot dogs, I would tell them where to place that million dollars, and that place would hurt afterwards.