Even as a lifelong Montana Native I still am in awe of this place. Plenty of hiking trails, fishing possibilities, and fairly large, mostly separated camp spots. We loved our stay there.
Was posted online as "reservations only" but the host allowed any non reserved spots to be taken.
Our only issue was that the reservation system (in New Mexico I think) charged us double what the price was supposed to be. Getting a refund was pretty much impossible due to the bureaucracy of the gov't system.