We are planning on staying in Custer S.P. and the badlands area. Looking for advice on biking options for my family. We'll need to rent bikes but would like to do something a bit more involved than a 1 or 2 hour ride. My boys and myself are avid mountain bikers... My wife.. not so much. But she does like to ride. Can anyone suggest a trail or area that may be a little challenging for us but not to overwhelming for my wife. Many thanks in advance for your recommendations and help.