I was also trying to measure on google maps, but there are so many trees in the part of the park right after you enter that it's hard to route a path. The best I could come up with was similar to
Anyway, a couple of other things - The handicapped parking area is quite large and if you are parked in one of the farther parking spots, the walk will be a bit farther. There are benches along the way where you can stop and rest if you need to.