Last time I stayed there the hotel policy was no outside guests. However, I believe last year I heard that they were open to outside guests who wanted to dine in the lodge. So perhaps that is true. Sorry that I do not have a definitive answer but I would say call or email them or even just stop by. If you are there now and you stop by you can simply ask to tour the property to get a look for future stays. I have done that at many properties before and they have always allowed it....that was how we found Catcha Falling Star years ago. And typically once on the property they are more than happy to serve you a drink or a meal.
Hope you are able to check it out, it is a beautiful property for sure