Sounds like an exciting trip mate, plenty of freedom. I've not been to the states yet probably wait until the boys are a little older. South appeals although I've family in Vermont, don't think it would be much fun Christmas time lol. My standard thing is try and be spontaneous, at the same time as thoroughly organising everything you definitely want to do , I use Google review , TripAdvisor etc, with young kids I can't be particularly spontaneous outside of a random food or crabbing adventure lol. Make the most of it , plan rest days as sounds a long trip , I know you'll have a blast, also I'