Starting point: the small car park by the church in Bazoches-sur-Guyonne.
(S/E) Take the D13 with the church on your left, until you reach the Chemin du Château Bertin, on your right, which you turn into. You should see the red and white markings for the GR®11, which we'll be following for a while.
At the fork, turn left and go up into the forest. Follow the signposted path south and then south-east.
(1) At a fork in the road, turn right, even though the signs indicate that this is not the GR® (the base map, which has probably not been updated here, indicates that it is still the GR®). This part of the path can be quite muddy as the subsoil is waterlogged.
(2) At the crossroads, turn right. You will find the GR® markings again. You pass a villa perched on the Rocher Marquant. On your left, you will see a large white, cubic villa. This is the Maison Louis Carré, the entrance to which you can see at the bottom of the path. At the crossroads, opposite you, is Jean Monnet's house.
Turn left and continue down the tarmac lane. At the T-junction, turn right.
(3) Just before a fork in the road, leave the road and take the path down to the left. Follow the track down to a small stream (the Guyon), which you will need to ford.
Alternative: if fording is difficult, walk along the stream to your right until you reach a bridge, which you can cross, then immediately turn left to rejoin the original route.
Continue straight ahead (south-west), ignoring a perpendicular path.
(4) At the water treatment plant, turn left. You are now in Les Mesnuls. Turn left into Rue Beauregard, which bends left and then right. At the end of the right-hand bend, turn right into Rue des Champs. Cross the Rue Montorgueil and, at the next fork in the road, turn left into the Rue de la Borne. At the end of this street, turn right into Rue Neuve.
(5) Just before the church, turn left into the park. This is an ideal spot for a picnic. Join the D191, turn left and drive past the Château des Mesnuls. Turn right onto the small tarmac road, the Chemin du Moulin, just beyond the château's perimeter wall. You will pass by an old mill.
(6) At the T-junction, turn right onto the Chemin du Vieil Étang. After 50 m, turn left up the small path. Be careful, you may pass it without seeing it. Continue straight on to Les Essartons. There is a house on your left and a clear view on your right. At the crossroads, turn left and walk alongside the building. You will see the Notre-Dame du Chêne chapel in the distance on your right.
(7) Just before the entrance to the La Brocardière estate, at the gate, take the path on the left and head into the forest. Continue due west for approximately 800 m, ignoring the paths on your left or right. At a T-junction, turn right. After 50 m, turn left onto Chemin de la Jonchèe. Turn right onto Route Robert, where you join the GR®1, signposted.
(8) Turn left onto the path that runs alongside the Étang de la Plaine. Continue north-west to Rue de Château Gaillard. You are now in Montfort-Lamaury. Follow this road for several hundred metres until you reach Rue de Sance, which you turn right into.
(9) After about 50 metres, take the stairs on the left (ruelle Boutet). This will take you to Rue Maurice Ravel, where the house museum is located. If you turn left, you can cross the pedestrian crossing to go up to the Tour Anne de Bretagne. Head back down towards the town to reach Rue Saint-Laurent and then Place de la Libération. Opposite the church, turn left into Rue de Paris. Follow this street as far as the town hall. Pass under its porch to reach Rue Normande. Turn right into this street. You will pass Place Robert Brault, then Rue de la Moutière, until you cross Rue Christian Lazard (D 155), which you turn left into.
(10) Drive alongside the stadium, then turn right just before the wall of the Château de Groussay park. Follow this wall all the way round. You will pass a sewage treatment plant and then, on your left as you climb the hill, you will see the observatory column, one of the 12 follies of the château.
(11) At the top of the climb (hill 120), take the track on the right, on the plateau. Follow this track to the D191. Cross the road and take the tarmac road opposite towards Houjarray.
(12) Just before the bend in the road, leave the road and turn left onto a track which you will follow straight ahead until you reach the Chemin du Petit Gué, which will take you directly to the church car park (S/E).