exit 23 always going to Moultonborough - it may be a little longer than 28 or other backroads but the highway is less streeful to drive on.
We always just want to get there so even a grocery stop is rushed and avoided if we can. I doubt we'd ever stop to shop for any big ticket items on the way up. If I need anything like that I turn it into a separate outing with the kids.
Good luck with your venture. I bet fireworks right off exit 23 would be a huge hit!