To get to Gardner Dam it is probably better to go out Knickerbocker Rd past airport, over the dam, turn left, follow the dirt roads around west side of the lake. If you use Google Earth, be sure and turn on "ROADS" in the Layers. That will show you the road that wanders back that way. It is mostly dirt. Pavement ends at the ramp on the equalization channel but dirt road continues.
I am not sure, but don't think you can get back to Gardner Dam area from the other side of the lake. And I make no guarantees on either since it has been 20+ years since I went back to Gardners Dam in a car or boat. Just wish the lake would get about 5-10' more water so we could fish the South pool.