i have not paddled it but i have spent a lot of time out in T roosevelt NP. our family used to go out there for the wide open spaces.
the river varies from flash flood to dried up. make sure there is water. the river bed and banks are sticky mud, but it is a beautiful area and would be a blast to canoe.
the usgs gauge at medora gives a good idea of what these rivers do.
that is a scary graph, i would not want to be on the river when this happened. thing is the river is long and a thunderstorm one hundred miles away may have caused this. just a heads up.
this is the white river, SD, after a very heavy thunderstorm, it was almost dry the day before. fun canoeing. bad water.