I Canoed the Ottertail last month.  We went from rice lake down to Little Pine? 10-15 water miles. It was a very nice section of river. Only two old docks on the river and did not see any boats or any other people. You paddle under 3-4 roads and we portaged over a highway and railroad tracks.  water was a little low in some spots but we never got stuck. The scenery was great and the shoreline was undeveloped except for a farm and a cabin or two right above Little pine Lake.