Here are a few retreat centers from diverse traditions in Vermont:
Benedictine Priory, Weston, Vermont
Green Mountain Monastery, Thomas Berry Sanctuary, Greensboro, Vermont
Happiness Paradigm, Calais, Vermont
Karme Choling – Shambala Meditation Center, Barnet, Vermont
Metta Earth Institute, a center for contemplative ecology, Lincoln, Vermont
Milarepa Center, a Tibetan Buddhist retreat center, Barnet, Vermont
Pema Osel Do Ngak Choling, Buddhist study and practice center, Vershire, Vermont
Sky Meadow Retreat, Stannard, Vermont
one list of retreat centers in Vermont here