When you are driving out to OLCC on 192, you'll pass Silver Lake Resort on your right, Westgate Vacation Villas on your left. At that traffic light, the road leading to Silver Lake is Sherberth. This will take you to an access road that intersects with the entry road for Animal Kingdom's parking gates. Or drive away from AK and follow the signs to the other parks. Returning, you follow signs to AK and look for the "authorized traffic only" sign on this access road. It's a public street but not designed for large scale traffic, so they don't have regular signs.
I may have missed a step or a turn in these instructions. But the front desk staff at OLCC will certainly know about this back way to the parks. So ask at check-in. Also, there are many shops near the intersection of 192 & Sherberth. Ask in any of those. Hope that helps.