I'm just starting and I live in spfd, mo. A good place to try is the train yard near the square, closer to grant and chestnut. I think that's where it is anyway. It's got giant tubes to climb through, on, and between with piles of construction bases and other big stuff you can trick off of, jump between, and generally kick the shiite. I don't know how many people can see you out there in the day, but I go at night anyway. Also another good place is elementary school playgrounds.