If you have access to a wide open park, then it’s a great time to think of all the activities that you and your friends can do on it. You could bring your drones and fly around the field. You could also play popular sports such as football and disc golf.
The latter is particularly suited to this kind of environment. You don’t need a specific field dimension just to play it. Just aim and throw towards your target. Of course, it would help if you had great discs with you.
Be sure to bring a good distance Frisbee to give yourself a headstart. This should have sharp edges that can slice through the air to reduce drag and help them travel as far as possible. Their mass should also be distributed more towards the rim to provide higher angular momentum.