This handy map will, I hope, prove handy. The building marked 18 is the College of Arts and Sciences building, the western end of a long structure that stretches between the BU east and BU central stops on the B line. We have access to room 221 (and maybe others near it), on the second floor. The outdoor tables are right behind that building; if you go through the chapel plaza and look right, you'll see them. If the weather is nice enough we'll probably be (at least partly) outside.
The space is reserved for us from 2 until 11 pm.
There's probably parking in front of the building, but it's never guaranteed. If there's a Sox game or something it could be bad.
If you need a broader context in which to place this block, go to the BU map page.