Where is the best sugar house in Vermont?

The ones run by the Madame called Sugar?

What part of Vermont are you intersted in?
IMO, the best sugarhouses are the ones you don't see in your tourist brochures. Stop in the local general store and ask if any local sugar farmers welcome visitors. You'll find that many do.
Have fun!

When is the season for harvesting?

Bardo: in early spring, when the snow only starts melting and the trees "wake up".

bm,
During my early reading years, I used to be fascinated by "sugar on snow", which I encountered in books by Laura Ingalls Wilder, among others. Is this still served at sugar houses, church socials, etc., whenever the maple syrup harvest and a fresh snowfall coincide? I believe the traditional accompaniments were plain doughnuts and bread-and-butter pickles, along with hot coffee. It sounded very exotic to a little California gal.

Last summer we visted the BRAGG FARM near Montpelier/Barre. Of course it was summer and they aren't actually making maple syrup then, but we saw a short movie and talked to them about it.

It is one of the last ones (if not the last) to use wood fire and also they use buckets on the trees rather than a network of plastic tubing.

They sell the syrup in different grades and also do mail order. I loved the grade B (the darkest, most flavorful type) so much that I got myself 2 gallons by mail last fall and enjoy some on yogurt every night!