Turns out it's actually a good thing I couldn't find the monument on the map. If I had, I would most likely have chosen Crosby-Lynchburg Road and tried to take the Lynchburg Ferry to the monument grounds. But the Lynchburg Ferry was closed at the time! In fact, I later found out it shut down that very day, for a period of several months. The long confusing route I ended up taking happened to be the most direct route possible at the time.