Sounds like an awesome thing to do! I am jealous. I want to go for a ride in central park.
Last week. I actually cantered a 20 meter dressage circle!

Buck was being a good boy the entire ride in our big jump ring. Walk/trot/canter in a nice, easygoing balanced way. So I decided to try a small canter circle in the dressage ring. He broke into a trot going down the line to B, but picked the canter back up when asked and turned at B and stayed nice an balanced all the way around the 20 meter circle. HA HA! Our first time. (Buck has been getting back in shape since he wasn't ridden much before May and he had a very weak back end as he was a western horse and use to be very heavy on the forehand). We then just rode on a very loose rein around the entire property under the trees. It was just an awesome day!
Haven't ridden since Sunday as it has been raining all week. Suppose to have a lesson today after work, but clouds are rolling in as I type.
Any other riding stories out there? This is fun!