I think if you’re going to take that sidewalk path going east you’re better off just using the Washington Blvd on-ramp just outside of the frame to the left of that picture:
[ATTACH=CONFIG]3506[/ATTACH]
You can then cut onto the path:
[ATTACH=CONFIG]3507[/ATTACH]
On the other hand, if you’re coming from the right lane you do have to go about a meter in the wrong direction, but there aren’t that many cars coming out of the Pentagon in that spot so it’s not really that bad.
The gravel section you have indicated is indeed pretty dangerous and it would be good if they either fixed it or rerouted bikes around it somehow.