There is a really nice state park (Smallwood State Park) about 15 miles west of LaPlata, MD (which is about 12 miles north of the Harry Nice Bridge). You would take Hwy 225 (Hawthorne Rd) and then Hwy 224 (Chicamuxen Rd) to get to the state park, so it is all easy driving on super wide 2-lane roads.
We live about 7 miles from Smallwood State Park, so we stay often. Huge sites, water + 30amp, dump site on your way out. VERY quiet. We have a 43' long fifth wheel that is 13'6" tall and we can fit on a bunch of the sites, even though they say max length 30'. The sites have enough room for the camper, tow vehicle AND an extra vehicle.