The walk starts from the church in Sérézin-de-la-Tour, a small village in northern Isère, south-east of Bourgoin-Jallieu.
There is limited parking near the church. However, there is a large car park at the edge of the village on the road to Nivolas Vermelle.
(S/E) Leave the church square and head towards the centre of the village (due south). You will soon come to a crossroads (signposted "priorité à droite" or "give way to the right"). Turn left onto the Route de Saint-Victor, then immediately left again onto the Chemin de la Perrolière.
(1) You will come to a sign for "Poizat - 295m". Turn right. At the next crossroads, turn right again. After a sign for "Magnier", you will come to a "Stop" sign. Go straight ahead. Continue along the small road. It will turn left.
(2) You will pass Magnier Castle on your left (first behind a wall, then visible through the entrance gate). Your small road turns again, but to the right. At a fork, take the left branch.
(3) As soon as you see a dirt track leading off to the left, take it (yellow markings). Enjoy it, as it's pretty much the only shaded section. After a while, you'll come to another track. Turn right.
(4) You will come to a small road. You will see a sign for "La Goutte 349m". Turn right. Follow this small road until it meets another road (T-junction). Turn left.
(5) When you reach a crossroads, turn right (yellow markings). You will come to a T-junction, where you turn left.
(6) You will enter the scattered hamlet of Fichaillon (sign: Fichaillon - 419m). Continue to the right, before an enclosure with two ferocious dogs and a beautiful old house with a round tower. At the next fork, turn right. Continue along the rocky track until you reach the hamlet of Quinsonnas.
(7) At the sign for "Quinsonnas - 433m", turn right. At the fork, turn right again. You will pass in front of the castle and its imposing gate (but look for the fence on either side of the gate...). Continue along the path.
(8) You will come to a small road, which you follow to the right. When your road turns left, continue straight ahead.
(9) When you come to a garage door, turn left and continue until you return to the starting point (S/E).
The description is accurate and reliable.