We stayed at Le Cagnard about 15 years ago - the road up there is very narrow and we actually scraped our little car, which was traumatic since it was one of our first trips to Europe.
We stayed in one of the rooms that are built into the ramparts which can best be described as the "Flinstones meet the Jetsons" in decor. It had the feel of a cave, but had a bunch of features that could be controlled by a remote - kind of like a bachelor pad - flick the remote and voila the drapes close, the lighting dims.
They were training a new dining room staff when we were there - in fact there could have been new owners. In any event, it was very strange, although the food as I recall was delicious. The staff kept dropping forks, misplacing the zillion changes of cutlery and were constantly glared at and reprimanded by Madame, who I presumed to be the owner.
When it was time to leave they could not locate our car so we cooled our heals for over an hour while they frantically looked for it. All the while Madame was on the phone carrying on about Americans, some of the other guests and all kind of things, 80% of which I could understand.
Sounds like others have had good experiences - it is definitely in a lovely setting and lunch on the terrace would probably be very good.