This is very true, I keep my boat on St. George island at the corner of the St Mary's river and the Potomac river. Winds out of the south east, can build some decent waves in that area (30+ miles). And two storms hitting each other at a pretty large intersection can get pretty dicey.
There's St. Mary's yachting center (used to be Denis pt. marina) Lots of options on the coan river and yeocomico. Bluhaven Marina, point lookout marina, tall timbers, etc. Google those and call around. A lot cheaper than Solomon's or Annap.