Just my $.02 since I'm from SD....
I don't think a base closure in RAP will have too much of an effect on property value, even if it were to happen any time soon which I doubt. The reason I say this is because people from across the nation love the Black Hills and end up buying a lot of vacation homes or, as with the billionaire moving out there, permanent homes. A guy from my company got hired to fly his GV. Straight to the left seat...right place, right time. At any rate, I'd say don't worry about it. I only see property value going up around there due to location.