Wow! My boyfriend and I did the 5 day Salkantay Trek with Inca Trail Reservations in June, and it was an experience we will never forget.
I was very nervous going into the trek, as I am not in the best shape, but this trek is very doable (although challenging!!!). Our guide, Juan Carlos, was incredibly resourceful, kind, experienced, and flexible. He knew how to pace the group, while balancing challenge with feasibility. He also knew how to make people feel better when injured or feeling sick! The course he took us on was different than a few of my friends who had done the trek before (as in, where we were each day), and I actually really enjoyed the way this tour was broken up more than what my friends had described. We caught every view and had the toughest day our first day!
The views on this trek were out of this world, from the lagoon to the Milky Way to Salkantay Pass to the valley to Machu Picchu. Something that cannot be seen any other way; you will truly come to understand the deep connection between the Incan people and Mother Earth and feel it yourself.
Definitely take care of packing with many layers and bring your best, broken in, hiking boots. We rented poles and were very glad to have done so! On the fourth day we opted to zip line half the day, which was a lot of fun. Our group was awesome! Also, I cannot write this without giving a shoutout to the chefs and staff. They were powerhouses and provided us with the best possible experience and cuisine!
Go for it! You can do it and will have a wonderful sense of accomplishment afterward.