I live North of Sartell and have fished the river a good amount. From the landing on the East side to the South there is really nothing to be concerned with, but straight out from the landing and a bit North (sorta right in the middle of the river) there a rocky sunken island. It does have a buoy on it, but not sure if they pulled them yet.
Going North from there the typical premise applies to regular “river navigating” in that the deepest water is on the outside shoreline.
I noticed the newest Navionics chip has the river mapped now, but I haven’t been out on the river in a while to verify its accuracy.
The Country Park referenced by Ralph is several miles upstream and you can get there without too much problems or concerns, but past there, you really need to know where you are going because it gets sketchy in a lot of places. The Fall the river is the lowest of the year and what may have not been a problem earlier, now will be for sure.