Perched at an altitude of 1700m above the valley, this hike from Modane is a good warm-up (750m of positive ascent), mostly in forest, to enjoy on days when the sky is cloudy. The ascent is very steep but effective to reach the route de l’Orgère and the fort du Sapey, which you walk around, and the descent via the fort du Replaton is rather pleasant with beautiful views over the valley and the border massif. An easier variant is to first reach the fort du Replaton and then climb towards the fort du Sapey in a round trip. Unfortunately, the forts are not open to the public. To get there, park on chemin du Replaton above Modane (3h00).
Located right next to the Tour des Glaciers de la Vanoise and the GR5 (La Loza), Chalet de la Fontaine is ideally situated for exploring the Vanoise on foot (shuttle buses also run to Aussois and the Bellecombe Termignon parking lot). The Arpont, Plan Sec and Entre deux eaux refuges are between 3h30 and 5h away. There are plenty of itineraries and variants to cover the Vanoise National Park over several days of hiking. Valérie and Stéphane will be happy to give you more information about the hikes.
At an altitude of 2,000m in the heart of the Vanoise National Park, a visit to the Chappe telegraph station at Mollard-Fleury is well worth your while. Free tours are available thanks to the association Histoire Archéologie et Patrimoine de Sollières-Sardières. To get there, there are signposted routes from the Monolithe de Sardières car park (1h20).