It's a 10 minute walk from the center of things. One pleasant surprise in Chamonix was that all shop keepers, hotel clerks, and the tourist information office were more than willing to speak English and be helpful. The latter, which we chose, is slightly longer but avoids difficulty in getting space in the Gouter and the great risk of stone fall below the hut. The two-stage tram is as packed as the rest of the town. Make reservations ahead for a specific day and time.
Reservations are necessary at all of the huts.
Once at the upper tram station, with all of the pictures taken and snack food eaten, push your way through throngs of white-knuckled tourists gaping over the edge. Walk to the ice tunnel which leads to the knife-edge ridge which starts the Cosmiques hut route. It is an exciting start for a great climb. Steep, very narrow snow at the start mellows out to a standard glacier traverse to the hut about an hour away. Non climbing companions with good glacier travel skills and all the gear can have a great outing by going as far as the hut - as Julie Wilson did.