Bradley, like Benson (and Bass and Bush) lost because New Hampshire has had a huge influx of anti-Republican voters.
FACT: The people that are moving up from Massachusetts are voting for Republicans. It's the moderate New Hampshire natives that are voting overwhelmingly for Democrats. Independents are voting for Democrats at almost 70% in New Hampshire right now.
Hate to dig a topic, but you're absolutely correct. The Boston exurbs in NH are still mostly Republican. This also explains why San Joaquin/Stanislaus/San Bernandino/Riverside all swung sharply to the GOP in 2004; because it's people fleeing the high land prices of the Bay Area/LA.