I'm in the accelerated program and our clinical sites have been:
Adult health: BMC, Beth Israel-Needham, BIDMC,
Psych: VA-Brockton, McLean, Emerson
Maternity: BIDMC, St Elizabeths, south shore hospital, good samaritan, Cambridge hospital
Community: VA-JP, Norwell VNA
Peds: BMC, Boston childrens, Newton-Wellesley
Our preceptorship sites are supposed to also include MGH and Brigham & Women's.
I've heard some of the traditional students clinical sites to include the above plus MGH, Brigham, Cambridge public schools, Boston-area community health centers (so many to list!).
The only big hospital I haven't heard of any UMB student being at is Tufts...but again I don't know where past students may have been out if that's anther option for traditional students.
Hope this helps!