It's a mixed pavement/gravel road tour. Leaves Helena, goes over Boulder pass, roughly at 1300 ft elevation climb over the pass. Then drops into the (higher) valley to Boulder Hot Springs. In terms of difficulty, it's not a lot for a 20 something, but my wife and I are upper middle aged, so it's a bit more difficult for us. The route goes in parallel with the Great Divide trail, and in a couple of spots they meet.
Day 2 will be a tour of the Boulder valley - very little traffic; but good views, nice scenery. Low mileage, but it's about the tour; not the distance.
Day 3 is to climb back over Boulder pass and head home. The climb isn't as much in elevation, roughly 800 feet of climb; but will hopefully make for an amazing adventure.