Lums Pond SP DE, Tuckahoe SP MD or St. Michaels MD

I think Tuckahoe SP is your best choice for day trips to St. Michaels. It's the closest for sure. We've camped there several times, and it's a popular park. We usually camp at Martinak SP (about 5 miles East of Tuckahoe). That's a great park too, they both offer fishing, hiking etc.. Martinak has a boat ramp with access to the Choptank river, if you have a boat with you.

Have a great time!