If there's no parking on Arsenal for some reason, continue east until you get to the road into the park, and turn right there. In the traffic circle, go right. Follow the park road around until you see a small, T-shaped pavilion. Park near it and walk into the grass (to your right) and look for hashers.
On the map, the red foot-like thing is where we're meeting. The blue car-shaped things are where you can park. The path that says NO CARS is where PMS should not drive.