One of your first stops should be Missouri Breaks National Monument Interpretive Center. Here, you'll be able to find your bearings and get some great ideas before you set out exploring.
Located in Fort Benton, this tourist information center is well worth a look. But you'll find plenty more to discover in this area. Historic Old Fort Benton, Fort Benton Bridge, and Museum of the Northern Great Plains aren't too far away from Missouri Breaks National Monument Interpretive Center.