For any state park, try 151.235 and 151.400. I think that their LE folks also have 39.50 and 39.54 available as well as a possible presence on systems for the locality as well.
If it's Assateague National Seashore you mean, remember that it's a National Park, not a state park. Repeater outputs for them and for NASA Wallops Island are the 169-172 range, I think.
73/Allen (N4JRI)