In total, I was in the park for five days. I made the W clockwise, so that I could take the boat to the Grey Glacier on the last day, because if you make the trek to the other side, the boat goes directly to the Grey campsite and you do not see the grey glacier from close. It is also recommended to extend the W a bit and walk at the Grey campsite to the suspension bridges, because from there you have a great view of the glacier. (The green dots on the map are the campsites where I stayed overnight.)
Weather-wise I was neither lucky nor unlucky, it was typical Patagonian weather. I had during one day light rain and the rest was very varied, sun, snowstorm, rain and fog. But there was no completely cloudless day when you could see all the mountains perfectly.
If you want to know how to book the campsites in torres del paine, I recommend you the following website, which describes everything relatively well.
Basically you only need the following three links to make the reservation:
Las torres central campground
When I arrived in the park in the morning I went first to the campsite and left most of the stuff there to hike to the viewpoint Base De Las Torres. The hike is relatively easy in my opinion and can be done very well in one day. There are also many day tourists on this tour.
The second day is relatively simple – you just walk from one campsite to the next. You have a very nice view of the Nordenskjöld lake.
Paine Grande campground
The way to the Paine Grande campsite with a detour to the french valley drags, but the effort is worth it all, because once in the french valley the view is breathtaking. You are surrounded by massive rock faces and glaciers with a beautiful green forest in the middle.
From Paine Grande to Grey Campground is a relatively short distance, so it is definitely worth to extend the W and go to the suspension bridges from where you have a great view of the Gray glacier.
Ferrier lookout point
The highlight of the hole treck was definitely the Ferrier lockout point on the last day, because from there you can observe almost the entire W treck. If you walk very quickly, you will reach the viewpoint in an hour. It is definitely highly recommended.