Having spent plenty of time just to the west/northwest on and around the Tarn, I can't imagine the Cevennes is anything less than wonderful.
I don't know if its the same, but I have always been amazed that the incredible places like the Gorges du Tarn are basically empty and closed until mid-June. The busy season is very short, and half the campsites were still shut in late May. This is both a bonus, as you have the landscape to yourself, and a pain, in that some of the eating houses and accommodation may not be open. That said, I would highly recommend going just off-season. There will be something open, just find out ahead of your arrival....it took visiting 3 campsites (by canoe) to find an open one for us on the Tarn during our May Bank Holiday week.
In reply to Removed UserStuart en Écosse:
> Get yourself there. Tip: Le Camisard in Florac is one of the best places for lunch you will find anywhere, but check it's open.
Bu88er. It was closed. Doubly disappointed now. Though we did eat very well in a little "locals" place nearby.