The Salkantay trek was very fun. We had a good group and a good guide.
The first day is the most challenging, with four hours of uphill, and an hour of downhill. The lunch and dinner were very hearty and tasty. The night was very cold and maybe another blanket would have helped.
The second day was challenging due to the altitude. I had to stop frequently. The second half of the day was in the jungle, but there weren't really any bugs. Bugs came out third day with a vengeance so it would be good to say more bugs expected that day. The zip lining optional activity was very good.