The lodge sits on the mountain right beside the Machu Picchu entrance, about 50 meters from the gate according to Belmond. It is small, with 31 rooms and suites (29 rooms and 2 suites), set around subtropical gardens planted with native Peruvian species. The look is comfortable and low-key. You are here for the location, and everything else is built around getting you to the site easily.
Staying here changes how you see Machu Picchu. The entrance is about a three-minute walk, so you can be at the gate for an early timed entry, then come back to rest, and you are not tied to the bus schedule from Aguas Calientes. Entry still runs on timed tickets and set routes, so book those well ahead. Most guests arrive by train to Aguas Calientes, often on the Belmond Hiram Bingham from Cusco, then drive about 25 minutes up to the lodge. Meals are at Tampu, the main restaurant, the casual Tinkuy buffet, and Tampu Bar, which leans on pisco.
This is for travelers who put Machu Picchu at the center of the trip and want the most time there with the least transit. One special night here works well, often paired with a stay lower down. The caveats are real: it is expensive for the size and style of the rooms, it is small and books up early, and there is little else to do up on the mountain. Around midday the area by the gate gets busy with visitors coming up from town.
Sanctuary Lodge is the only hotel at the gates of Machu Picchu, a few minutes' walk from the entrance. It suits travelers who want to be at the site early or late in the day without riding the bus up and down from town, and who are willing to pay a premium for that position.