My first recommendation would be to register immediately for the ticket drawing at redsox.com that will be held for Yankees tickets. If you get selected, you'll be able to purchase tickets anywhere in the ballpark at face value. If that doesn't work, there are five other options:
1. Scour eBay for poorly advertised Red Sox/Yankees tickets. Every now and then someone leaves off the date, the team, or some other important indicator in the auction title, and a ticket sells for below face value. Even if you don't find an auction like that, sometimes you'll be able to find someone selling just 1 ticket for about 2-3 times the face value (~$150 for a decent seat in the rightfield grandstand, for example.) This is a much better deal than buying from a scalper on game day.
2. Check aceticket.com, stubhub.com, craigslist.org and other online re-sellers. If you're willing to pay a hundred dollars for standing room or a bleachers seat, you should be fine with this route. Also try calling this place:
Mr. Music Guitar Center Fender, Gibson, Bass, Amps- Allston, Massachusetts. They sometimes have good deals on Red Sox tickets at a 50% markup.
3. Go to Fenway the day of the game and hang out by the uniformed Red Sox personnel outside Gate E, about 2 hours before game time. People with extra tickets can go there to legally re-sell their tickets for face value to Red Sox staffers who then try to re-sell the tickets again (at face value) to anyone waiting in line. This is risky, especially for a Yankees game, so if you want to be 100% sure of getting in, I don't recommend this option. I've tried it 4 times (never for a Yankees game) and it worked for me only once.
4. Go to Fenway the day of the game and wait outside Gate C several hours before the game (probably 4+ hours for a Yankees game.) Anywhere between 1,000-2,000 tickets are available at face value for day of game sales and these are sold on a first come, first serve basis. The Gate doesn't open until 2 hours before the game but people line up much earlier than that and enter immediately after buying tickets (per Red Sox rules to avoid subsequent scalping.) I tried this once for a Friday night Red Sox-Yankees game. While I ended up with great seats, I had to wait 3 hours in line, then another 2 hours for the game to start. It wasn't an enjoyable experience and I won't be doing it again, at least not for a Yankees game. Against other teams, the wait might be shorter.
5. About an hour before game time, search for befuddled tourists and/or non-professional scalpers with extra tickets to sell. They don't know the ropes and will sell their extra tickets at face value. I've never tried this for a Yankees game, but this strategy works for me about 20% of the time.
Given that you're coming from out of town and understandably do not want to waste a lot of time around the ballpark looking for a ticket that may never come, I'd suggest one of the first two options, which are sure things and not as expensive as buying from a scalper before the game.
As for breweries, there's:
Harpoon Brewery - Brewers of Harpoon IPA and UFO Hefeweizen
and right next to Fenway Park, there's:
Welcome to BEER WORKS - BEER WORKS © 2008 (beware, very crowded and rowdy on game day)
and it's sister brewery in another part of Boston:
--BEER WORKS-- LOCATIONS
For another beer experience, you could take the Samuel Adams Brewery Tour in nearby Jamaica Plain (accessible from Boston via the red line.)