The rules were explained to me essentially as described by Thom 02099. One additional way of explaining to me was that the pass to get into the park is by defination a "vehicle pass" a trailer/ 5er, etc is not self propelled therefore it is not a vehicle. All this made no sense to me and was not this way when I had stayed less than a year before. It was also explained that this was not a change in the regulations, but rather a change in the intrepration of the regulations. In my words just another way for Colorado to get money.