I was there last autumn, and I'd definitely recommend getting an early start. The morning fog was still hanging over parts of the hills, and when it cleared the views were amazing. We chose one of the circular walks because nobody wanted to double back along the same path, and it ended up being a really relaxed day. One thing that helped us was checking the local hiking information beforehand. I used https://tourisme-nexon-chalusfr.com/ to compare a few routes, see which viewpoints were mentioned, and get a better idea of the distances. It wasn't about following everything exactly, but it gave us enough confidence to plan the day without constantly checking maps on the trail. Also, don't underestimate how uneven some of the forest sections can be. My friend wore lightweight running shoes and regretted it after the first hour because of the loose stones and tree roots. Proper hiking shoes made a huge difference for me. We packed a simple picnic and ended up spending almost an hour just sitting near one of the panoramic spots because it felt too nice to leave.