Following waterfronts is almost always interesting. Moving north along the Chesapeake Bay in Calvert County, the best way to stick as close to the water as possible is to use a variation of the Right Hand Rule for solving mazes: since the wall of a maze, like the edge of the water, is topologically continuous, if you keep turning right when faced with a choice, all the corrugations will unfold and you'll always make progress.
Glancing at the map before leaving, I noticed that Governor's Run Road in Kenwood Beach was only a few hundred yards through the woods from Aspen Road in Scientist's Cliffs, even though these two neighborhoods are widely seperated by car. Out there in the heat and humidity, I found exactly what I was hoping to find: a well maintained but unmarked trail linking these two roads. A desire line, blazed, no doubt, by kids walking between neighborhoods, and perfect for a high speed bike run through the woods.