D'OH! Took three glances at this thread for it to hit me...clearly I need more sleep.
Anyway, the most likely place to find the Pyrates Royale will be at the Maryland Renaissance Festival, which will be in the middle of its run while you're here. And it's just outside Annapolis, so it would be easy to get to. The Pyrates are regulars at the RenFest; usually doing 3-4 sets a day and they've got a little compound in the middle of the site where they hold court when they're not performing. And there's plenty of good music and shows there besides the Pyrates.