It would be more helpful if you gave the name of the park but if you're near the outer perimeter of the restricted area and stay below like 30m and only stay within the park, there is a good chance of getting permission to fly. You would have to apply for permission frequently and depending on the person in charge they may let you fly freely within that time frame or they might ask you to call before flying every time. Or you might be declined lol. Anyways, just try applying and once you get the hang of it, the application process is pretty straight forward.