We've been up that way each of the past 4 summers (once in a car and three times on the m/c). If you already know what follows, please feel free to disregard.
The ferry from Port Kent NY to Burlington VT is approximately a 1 hour boat trip. Drops you right in the middle of Burlington downtown. We've done it past 2 years. Nice way to relax and cool off after riding up through the "Lakes". (Saranc Lake, Tupper lake and Lake Placid). At the Olympic ski jumping venue you can take the ski lift to the top and ride big inner tubes down the hill. Speeds hit 50 mph or so. (I passed on the opportunity).
In NH, Routes 302, 112 (the Kanc), 2 and 16 are good routes. If you get to Franconia area, check out the Franconia Notch Gorge state park. Even if you don't get too far into Maine, take a look at Rt 1A which runs from Hampton Beach NH up the coast thru Rye Harbor to Portsmouth. Very scenic and gives you a little taste of the coast.
Mt Washington has a web site to check conditions at the summit (temps, wind speed & visibility).
The area near Lake Winnipesaukee is nice and scenic. Laconia and Wolfesboro are popular towns near the lake.
Depending where you cross Champlain, there are several good options to cross VT from west to east. Rt 2 runs parallel with the interstate and after leaving Montpelier pick up 302 to 112 into Lincoln and the Kanc
Rt 4 out of Rutland will take you up over Killington Peak and through Woodstock VT.
To the south Rt 9 is a nice ride across the southern portion of the state. Rt 7 runs north to south on the western side of the state.
We just returned from a 13 day trip to SD, WY and MT, otherwise I'd be interested to join you. NE is always a great area to ride.
Stay safe, and enjoy the ride !