Note that Boston English often includes a little of a French influence. I forget the actual term, I believe it is elision. Anyways, rather than "Pahk the cah in Hahvahd Yahd" you tend to hear more of a "Pahk the cah-rin Hahvid Yahd." The r shows up VERY slightly because the next word has a vowel at the beginning, much like as in French.
Also, the "ard" in "Harvard" doesn't come out as an "ahh" but rather an "ih" sound. Similarly, "Danvers" is "Danviz," "record" is "reckid."
Finally, the correct response to "Do you Pahk your cah in Hahvid Yahd?" is, of course, "Whattah you, RETAAAHDED?!"