"Pomona is part of the Claremont Consortium which includes Harvey Mudd, CMC, Pitzer, and Scripps all withing walking distance of one another. Each of these could give the New England BS impression. Caltech in Pasadena is very a very compact community, too. "
Boarding schools in MA are nothing like the Claremont Consortium or Cal Tech, first would be the difference in the demographics, boarding schools in the northeast are predominantly white, Cal Tech is predominantly Asian. There is zero similarity, and I would not suggest that anyone who likes their boarding school experience in MA to attend Pomona or Cal Tech. Totally different environments.