Dan River in South Boston this time of year can be very shallow. As far as navigating it just depends on how far up or down river you want to go. There are rocks up and down river. The set up river is just above the rail road trussel in South Boston. The set down river is just before you get to the airport. You will go under a set of power lines down river about a half mile is a turn to the right the rocks are just below that. The depth at the boat ramp varies this time of year from about 3ft to 1ft.
Best have a shallow running boat. 90% of the time it's stained to muddy, not a bad ramp but have your motor tilted up all the way. The current WILL push your boat to the rocks alongside the ramp.