There are plenty of apartment complexes to choose from that are very close to the hospital, but I am not sure if they'd allow 3 months only. I don't think there are many furnished apts in Rapid City and sublets are probably not advertised. Your best bet is to check out the Rapid City Journal or to just rent a motel at monthly rates. If she decides to check out apartments anyway, I could give you some really great ones to check out.