I looked up my notes for areas I enjoyed.
Le Calvaire is a fairly short walk from the Avon train station and has a fun Orange Circuit.
You can take a train to Nemours and then a longish walk to Petit Bois which has Yellow, Orange and Blue circuits, unfortunately in a damp woodland setting, so a spell of dry weather is necessary to make them worthwhile. Nearby, Mt. Sarrazin's Orange circuit occupies a higher and dryer hillside.
It is about an hour walk from Avon to Mt. Ussy which has popular Yellow and Orange circuits, as well as a less well known but highly recommended Yellow circuit starting near the Roche de Hercule that feature a lot of continuous movement on rock features that link many of the problems.
You can take a bus to the Buthiers Recreation Centre that offers a Yellow and 2 Orange circuits. I managed to send 73 problems in a single day here.
Rocher de Avon is about an hour's walk from Avon, but being more popular, is more polished, and in my opinion less fun.
I did a lot of easy highball problems where, without a pad or spotter, a fall could be quite consequential. I enjoyed the challenge, but I realize that this is not to everyone's taste. I wore a helmet - a broken leg isn't any fun, but it is a lot easier to recover from than a fractured skull.