Do you bring your own beer

Definitely bring beer (and tip money) your tour guide also acts as a bartender at multiple stops.

Yes unless you only plan to drink in and at the bars you stop at(can't take from bar to tavern). It's an hour and half to 2 hours with 3 stops 15 min each. Only take what you can drink on the tavern. I recommend 2-4. Depends on your intent. So that's 5-7 drink in the tavern time if you drink at each location.

Yes