Ride there most of the time. Its slightly visible from I-75 (North Bound) right after you cross the turnpike, on your right. Most folks used to get off on the grass median and drive down under the bridge. However the Quad police have blocked that off.
The site is stilll accesible from various other routes. However you need to be careful, the cops have gotten wind of all the riding at the site and they are hovering like flies on sh*t. Other than that the riding is good, lots of mud pits, there is a section with endless whoops, several trails (when it rains forget about it) and then there is the "lost lake". ITs just that, a lake right smack in the middle of all the riding.
If you are still interested in going let me know and I can give you some directions.