Lower rim access
This route is the easiest and least fun way to access the quarry, but it will get you there. Park in the end of the neighborhood on Waynescott Road and enter the woods to the left of the house with the American flag. There should be a trail to follow that will take you right to the water. You'll have to pass a "No Trespassing - Private Property" sign, but that's how you'll know you're going the right way.
Upper ridge access
Park at the Ridgewood Baptist church at 2720 Lilly Road and enter the woods near the "No Trespassing - Private Property" signs. If you weave through the woods, you should find a trail that will take you to the upper ridge of the quarry. You can walk the entire distance around the lake (1 mile) on this path and there are a few treacherous routes from the rim down to the water if you want to go in. This route is by far the hardest and longest way to get to the water - courtesy of the boys' cross country team circa 2014.
There's usually no one patrolling this site, but sometimes they pay a teenage guy in a kayak to sit in the middle and yell at trespassers. Every person I've encountered is pretty friendly and will let you off the hook if you just apologize for being at the site and promising to leave. You won't get in any trouble unless you're bringing in illegal substances.
Have you been to this site? What did you think? Leave any tips of your own or observations in the comments to help other explorers!