Boston has commuter rail lines now that go 50+ miles outside the city...commuters in SC4 would not travel that far, plus that'd be a HUGE region. However, there are very few people who commute to Boston from much further than that, because once you get past Providence, people would rather work in New York City. And Boston is the very top of the northeast megalopolis, so people to the far north are generally not headed to Boston every morning. I'd nominate Boston if you were going to do a region like 50 miles left to right and 80 miles top to bottom. A lot of big cities have the problem of commuters coming from too far away to make it feasible to duplicate in SC4. Washington, DC is the same way.