I have never thought of overnighting at one of these places, but if you are a Silver Sneakers member(65 or older) these places are all over the country and free of charge. Some require registration first to get a card to get in after dark. I have used Anytime fitness in Fla and Az, YMCA's and a few others. All of the ones that I have used are not in cities and are convenient to use when traveling. I have only used the tow car to get to them and I have noticed only parking for cars but can't see why if you get there later why you can't stay overnight unless there is a sign or town ordinance.