The left-of-center Swing State Project has done a yeoman’s job laying out the conditions for a Coakley win in this model, right down to the town-level. But worth a look as well, mutatis mutandis, for the conditions necessary for a Brown win.
This map of the “relatively” closely contested Senate battle between John Kerry and William Weld in 1996 provides as close a facsimilie of a “purple” — that is, winnable — Massachusetts as is possible. And the most important piece of it is Middlesex and Essex Counties, the very populous and very purple area north and west of Boston.
Needless to say, if you know anybody in the area who hasn’t voted yet, give them a call!