The fourth day of our trek we slept (in) at Campamento Italiano, and started the next day around ten. We filled up our water bottles at the base of camp, one of the huge benefits of the park, delicious water everywhere.
The hike to the next camp / refugio was two and a half hours, so we took our time. We planned on arriving at Paine Grande (camp and refugio run by Vertice) and relaxing for the rest of the day before we headed up to Glacier Grey. Paine Grande is the point of the W is where you catch the catamaran back to the buses, and back to Puerto Natales. You can either start you trek at Paine Grande, and go west - east, or like we did, start at Torres, and go east- west. We went back an forth about which hike would be the better. It really all depends on weather, which you never know what will happen. We crossed someone on the trail who said it rained all day, and we had perfect weather. And we were on the same trail. So it depends.
We had a reservation to sleep in the refuigo at Paine Grande the night we arrived, which happened to be an accident. I thought it would be a bit of a reilef to sleep in a bed, but it's a bunk situation, and we happened to be roomed with a group of heavy snorers. I think we prefer tents!
We got up early the next morning, packed day bags, and hiked up to Glacier Grey.
This leg of the trek is pretty long and steep, but worth every step. along the way, you get views of the glacier, and the glacier lake, so you have hints of whats to come.
The whole hike took us about 8 hours round trip, including a lunch stop. Once you get close to the glacier, you can really chose your own path, to how close you'd like to get. The trail just kind of ends, and you can just walk around. You also pass Glacier Grey Refugio along the way, which looked like the nicest Refugio we'd seen so far.
Most of the hike back to Paine Grande is uphill, and uncovered, so it gets quite hot. This leg of the trail was crowded, but we were lucky again and had great weather. We camped at Paine Grande that night, one of the more crowded sites we met on the trail. It services as both the exit and entrance of the W and O, so it was understandably full.