I will be visiting the Fredrick area soon and am not from MD. Any local beer or bottles distributed to MD (vs PA) that are a 'must?'
Check out Ye Olde Spirit Shoppe and they will help you out. Easily the best selection in Frederick. As for actual MD local beers, I would say that there are not any can't miss beers but would suggest looking for some fresh Double Duckpin by Union or Big Punisher by Jailbreak. Also check out Roasthouse Pub if you need a place for food and beer. They always have somethingn good on tap.
Monocacy Brewing in Frederick puts out some pretty tasty stuff, highlighted by Brewtus Coffee (Imperial stout) and their Riot Rye Pale Ale.
Go to www.seekabrew.com ; you'll be able to compare distribution for those two states and figure out what you need to search out. If you're looking for a brewpub for eats, Brewer's Alley is usually worth a visit when I'm over there.
I second this. Frederick Wine House has a decent selection as well. Also, if you're willing to drive to Hagerstown (about 30 mins away), Wooden Keg is excellent as well. Slightly further away in the other direction is Perfect Pour in Elkridge and is about 45 mins from Frederick -- their selection is massive.