No special access issues
Park at the main parking showed on the map and walk the recorded trail (about 15min). The area will be visible on the right side of Route du Mont Aigu just 2..3 minutes of walking after a big crossing/opening with a lot of paths. The start of the circuit is super visible, only 10m from the path. This is also an easy way into the main area. For the further rocks, keep to Route du Mont Aigu for another 2-7 minutes about. These rocks are splattered on both sides of the path.
There is also an optional western parking shown. This is the parking at Gorges du houx/Franchard Raymond, the walk in is about as far for the most western rocks. Easiest is still the parking shown on map on the east side of the area.