not sure on the realation to the old tower but here are some rough directions.
as you enter FBF you take the first left after the entrence. you will shortly pass the community garden (nursery) there will be a building on your that is used by the parks dept. there is a large parking lot in front of it the next building you will see is an abondend hanger that has a wooden wall to keep people out. this is were you'll make the left turn into the parking lot. drive up to the old hanger as you get closer you'll see a section of blacktop on your left with no markings on it that is the track area.
the track is situated between the parks dept. building and the abondoned hanger.
parking is within 75 feet of the track area not sure is the bleachers are still setup but if they are you can't miss em hope this helps.