I had a 28 ft motorhome and we pulled into a spot under a tree at the first set of out door toilets. Further on down the gravel road about a 1/2 mile or more there are large spots with covered tables, I am sure you can get your 40 foot down there but it is long and wash boarded road, If you take the first exit to Vogal Camp ground from Riverton, WY across from the gun range it is a shorter route. If you miss it and take the second it is 10 or more miles of washboard road. THERE ARE HUGE MOSQUITOS. huge. We had a great quite stay for four days. Good luck