I live in the Plymouth area of Central NH. Route 25 west and up along the Conn River on the NH side is another option. Cross one of the bridges into Vermont and take side roads at least up to St Johnsbury. Also the NW are just west and north of Littleton NH gets briefly into totality. There are quite a few country roads if you have Google Maps etc. although cell service is very spotty in that area of NH.. It will not get very dark but Bailey's beads, Diamond Ring will last longer and you might be able to avoid lots of traffic. It all depends on the weather. If there is a high probablility of good weather a couple of days in advance, the more people will decide to head north. If it is iffy or of course a poor forecast with a large synoptic storm about to hit.... then just sleep in.