I've never had the brew tour, but have eaten there and had their sampler. I can also vouch for loose cannon. Are you going to Baltimore specifically, or just somewhere in Maryland?
I've had many of their beers, and never found a bad one. They're all drinkable, and some are outstanding. The McHenry is a damned fine CAP, the Oxford Organic Amber is a tasty pounder, and Holy Sheet is a really good interpretation of Belgian-style Abbey Ale.
The only one I've had I didn't particularly like was Loose Cannon. I found it unpleasantly unbalanced, but I'm not a hophead; the green mist that attacked me when I opened the bottle probably put me off. If you're into hopsmacks, you'll probably like it.
The tour is pretty good and you get all you can drink and a souvenir pint glass for $5 afterwards.
I also enjoy the Loose Cannon, but it's definitely an east coast IPA. There is more malt flavor and it's not nearly as dry as many of the west coast IPAs.
I sampled most of the Heavy Seas line at a beerfest a few weeks ago. Everything I tried was good. Big dIPA, Peg Leg, Loose Cannon, and Holy Sheet were all good IMO