can't comment on the med school, but i did my undergrad at yale. NH is a small, somewhat racially and economically segregated city, and yale and yale-new haven hosp are the biggest and richest parts of the city. that being said, it's not an awful place to live. housing is avg price for NE (2br-1bath apt with laundry in the building ~$1500), not a great place to drive because there is very little parking around the univ. decent bars, great pizza, short train ride to NYC. i imagine it would be an all right place to train, because with the amount of time you will have to hang out, there is definitely an adequate social scene-- plus when you have a weekend or something, you can always go into the city.
hope this helps.
--oh, also i did research in the med school as an undergrad, and there were tons of opportunities. don't know if this has changed, but i doubt it.
cheers.