Rivals craters in the furnace enclosure

From Le Tampon, follow signs for "Plaine des Palmistes - Saint-Benoît" until you reach Bourg Murât. Then follow the volcano and cross the park until you reach Pas du Sable. Descend into the Plaine des Sables via a few hairpin bends, then cross the plain on the track until you reach the terminus: the Pas de Bellecombe car park.
Watch out for ruts on the track.

(S/E) Admire the enclosure from the viewpoint. Follow the path along the edge towards the north-east until you reach Pas de Bellecombe.

(1) Go down the stairs, the only difficult part of the day. Follow the white markers that will guide you every metre of the way, which are useful in case of fog.

(2) Near the stairs, climb up the small Formica Léo crater, which is great fun for children, or follow the tracks to go around it on the right (choice of route). The path is easy on the lava flows. Reach a crossroads.

(3) Continue straight ahead on the Rivals trail, leaving the path on your left that leads to the Rosemont Chapel and Piton de la Fournaise. Enter the less pleasant area of rough black rocks and climb up to the Caubet Crater.

(4) Continue for a good hundred metres.

(5) Admire two magnificent geodes and the view of a multitude of craters: Rivals Crater, Château Fort, etc. Access is prohibited because lava flows in this area and there are still hot spots.
Turn back and follow the same route you took to return to the car park (S/E).

Sunscreen is essential even on cloudy days.
Water.
Check the weather forecast, as it's not as nice in foggy conditions.
Leave early, as clouds often roll in during the afternoon.

On the way back, you can stop at the Rosemont Chapel by turning right at (3) or even combine it with Piton de la Fournaise by starting there and following the path on the left at (2).

From the stairs, take the Sentier Kapor on the left, but I'm not a fan of it.