Not a surprise that they're doing Generic R or D. Kuster is a legitimately strong candidate with a good personal brand.
However, Keene mayor George Hansel is a candidate who can legitimately win the general if he gets there. There are questions about his charisma or if he can win the primary. He seems kinda scripted, with a bunch of platitudes and buzzwords that ultimately mean nothing thrown in there, but he's by far the GOP's best recruit in the Kuster era.
The main way he can win the primary is by attacking his rivals' residency issues. His main two rivals are Bob Burns, who lives in NH-1, and Lily Tang Williams, who ran for Senate six years ago in Colorado. If he's able to downplay his pro-choice, pro-environment views and make the primary about connection to the district and service, he can win.
He could also benefit if the others all feed off of each other and he has more moderate Rs to himself. He does have the Sununu endorsement, which is big in my mind because it shows he really is the establishment/mainstream R pick (Sununu's endorsements don't seem really all that helpful on their own) and not someone hopelessly cut off from the party. I guess the main contest here is between Hansel and Burns. I have the suspicion that, true to form, the NH-2nd GOP will nominate Burns and blow any chance they have of making this competitive.