Definitely do a tasting room and, if you have the time, tours. I only set out to have a tasting room as a kind of showcase for consumers and local bar/restaurant folks. It became a large percentage of our monthly sales revenue. You'll sell lots of beer in growlers - pints, if your state allows it - and cases and kegs out the door.
Plus, there is no better marketing in the world than direct, face-to-face contact with your customers. Not only do they get a chance to taste and get to know your beers, they get a chance to meet and get to know YOU. Nothing builds loyalty and customer confidence better than creating a personal relationship with the people drinking your beer. Every person who walks out of your tasting room or away from your tours with a full growler and the memory of a pleasant experience at your brewery is worth thousands of dollars in marketing and advertising. And all you spent for it was a little bit of beer and the cash to build a small separation wall.
As for the separation itself, it was always my understanding that you need something at least 48" high. For our tasting room, I built a railing bar and placed stools there so people could sit and see the whole brewing operation while they enjoyed their samples. You'll need to clarify that with the TTB because mine was built and approved way back in '07. Things may have changed since then.