This was a good 18km day walk I did in August 2010 with 1000m of up/down, from Prapoutel at 1340m to a group of lakes (Les Lacs du vénétier) at 2157m. The walk starts out from the upper-most road or Prapoutel, and snakes through forested areas climbing quickly initially, and avoiding most of the ski runs.
After around 3.5km, you join a 4x4 track (very lightly used) which snakes you round the mountain until around 6km - then you’re back on a path. At around 6.8km, there’s a refuge, although I wasn’t sure if they were selling anything other than sheep-cheese… They did have a good flock of sheep - along with a big white dog guarding the sheep - and a sign indicating no dogs allowed into the area (and no hunting).
After the refuge, the path regains it’s steepness, and you slowly zig zag your way to to the lakes at the top.
I came back after exploring the lakes; however when I got back I realized that I could have carried on up the path to the Col de la Jasse - from where the views would have been ever better. I’ve marked this section on the map in yellow.
On the route back - there’s a nice Alpine-hut restaurant called Chalet des Cortilles. I stopped for a drink and Ice Cream, but they also do the usual mountain fare.