You can reach Chalet Le Floria a number of ways.
From Chamonix town: head north through the town centre and along Rue Joseph Vallot until you come to Rue Mummery on your left. Walk up the road and turn right at the mini-roundabout onto Route des Nants. Continue past some lovely old houses and little stone cottages for about 300 metres until you see a path on your left called Chemin de la Floriaz, follow this into the forest and keep following signs for Chalet de la Floria.
From Chamonix town: walk up the hill behind the tourist office on Rue de la Mollard up to the Brevent-Planpraz lift station. Turn right and go around the lift building, turning left into a field. A narrow path goes diagonally up and left to meet a stony 4x4 track, where you turn right and follow signs for Chalet de la Floria.
From Les Praz: on the western side of Les Praz, past the bridge over the Arve and near the old sawmill, you will find a footpath disappearing into the forest just to the right of the Peugeot Garage. Follow this (leaving the Promenade du Vorgeat on your right) and you will come to a path junction at 1195m. Cross the Petit Balcon Sud and take the wide steep path bearing right which will lead you up to the chalet. Once there, you can enjoy a drink on their stunning panoramic terrace with unbroken views of the Mont Blanc chain. It is also possible to eat your picnic here if you buy a drink.