The valley floor is covered with walking, running and cycling paths. For a lovely beginner and family walks, head to the centre of Chamonix and start by following the river up the valley.
The path continues past Argentiere joining with many trail heads shooting up into the mountains. It is tree covered and flat up until Les Tines, and is gently rolling thereafter. It is a great trail for there and back walks or you can continue on until you're tired then take the train back from one of the many stops you will be close to along the way. When you get to Les Praz, the trail drops off and can be found again by the entrance to the golf course.