I am going to Denver in a family vacation. We will total 9 persons with lugage and am in need of renting a 12-15 passenger van. All the car rental companies in the airport are booked out on that type of vehicle. Maybe some denver local can point me some small rental company that can help me out. I need to rent from June 11 to June 27. I am planning to drive to Yellowstone so any travel advise will be apreciated.