It may make sense to treat GPT31 and GPT32 as one continuous stretch. Resupplying in between is logistically difficult and requires several extra kilometers of hiking.
GPT31P begins at El Salto, or the intersection of highway 240 and Ruta X-560. Along Ruta X-560, which is a maintained gravel road, are several signs advertising Parque Aiken del Sur which is a private ecological reserve. Stay on the road until reaching a brown building with a sign out front that says “Lago Riesco.” Across from the building is another road which leads down to a dock. If the main gate is locked, there is a side gate a few meters further down the fence. Be aware that legal camping is sparse in this area.
The banks of Lago Riesco are heavily vegetated and steep, broken by the occasional small beach where camping may be possible. About half way through the paddle is a salmon farm located near the southern shore. The take-out is a long beach with a gravel road that leads up to Ruta X-550. It is possible to camp here, but the beach is covered in trash.
Don’t bother deflating your packraft, because it is easily carried to the put-in for Río Aysén less than a kilometer away. Exit onto Ruta X-550, cross the road and go through the wooden gate. A 4WD track will lead you to the river. There are some good put-in spots closer to the cables you’ll see running over the river.
The Río Aysén is a large and swift river with few obstacles. The take out is a small rocky beach at the base of a steep grassy bank. Ascend the bank, and make your way through the field. Left of the obvious buildings, you should see a faint road that leads to a wooden gate. Go through the gate and walk up the driveway to Ruta X-518, a rough and lightly trafficked gravel road.
The GPS route splits from the road just north of Lago Portales, but it is possible to continue to follow X-518 another 2 km to a nice put-in by an aluminum building. At the one split in the road, take the right fork down towards the lake.
There is no obvious camping on Lago Portales. The banks were very steep and heavily forested. Take-out is at a rocky beach near a residence. A 4WD tracks climbs towards a house and continues past it to a road. The road becomes a braided and muddy cow track that leads through brush down to Lago Zenteno. The put-in is a small and reed-covered bank.
There is no camping for the first several kilometers of Lago Zenteno. There are no beaches, only reed covered banks. Near the end of the paddle, there is an island that has nice camping and a few curious goats.
Take-out is a small beach 100 m from the island. There is a structure located here as well as a place to camp with a fire ring. Follow the gravel road that eventually joins with X-610. The road walk to Lago Atravesado is lightly trafficked, surrounded with private land, and fenced on both sides for most of the way. The put-in for Lago Atravesado is at the base of a dirt road that turns off from X-608. There is a small camp spot here with a fire ring.
From the put-in at Lago Atravesado, head south southwest to the disguised entrance of a small channel. The take out for the lake is a metal dock set upon a rocky beach. There are many flat spaces to camp here and up the grassy walkway is an open structure with long wooden tables.
Follow the grassy path past the hydroelectric dam to a set of stairs that descend down to Lago Elizalde. The put-in here is at the base of the dam. Intersect with GPT32 in the middle of the lake.