The short answer
Mount Princeton is a resort decision first and a town decision second. The property sits along Chalk Creek outside Nathrop, with Buena Vista close enough for dinner but not close enough to feel walkable. That means the lodging choice is really about whether you want the resort to be the whole trip or one stop in a wider Collegiate Peaks weekend.
Overnight guests get the easiest version of the experience because the pools, creekside soaking, resort facilities, and room are tied together. Day visitors can still have a strong trip, especially from Buena Vista or Salida, but the value equation changes on busy weekends and holidays.