Are you traveling in from the west?
Cherry HIll is doable. But it is a little far. Not too bad if you want to tour DC while in the area.
Patapsco state park has a decent CG and is pretty close to the Camden Yards.
Millersville KOA is a decent option as well.
For the most part you will want to drive in vs. public transportation.
There is a car rental about a 1/2 mile from Patapsco state park.
19'Duramax w/hips, 2022 Alliance Paradigm 390MP >BD3,r,22" Blackstone
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Porta Bote 8.0 Nissan, Sailun S637