The couple is registered at Amazon: https://www.amazon.com/wedding/registry/1NLYBPBKLAT3Q
The website is not entirely cooperative with the maps link. However, the powerhouse picnic area is available in Google maps. Follow 5th or 12th street over the lamoille summit. You can follow lamoille highway far beyond the roundabout. Continue for a while into Lamoille. There will be a sign on your right directing you to the lamoille national park. Turn right and follow the road up into the canyon. Powerhouse will be on your right, indicated by a large sign on the road.