I decided to do the 4d/3n inka trail in april. Hiking to the Machu Picchu was a really great adventure!!!.
We were a small group, 8 persons, it was really familiar ;) The 1th and the 4th day was easy, but the 2nd and 3rd day you should not underestimate! I would recommand walking sticks, especially for the 3000 stairs downhill on the 3rd day. I would also recommand to give your backpack to the porters.
So you can enjoy the hiking and landscape much more ;) It is not necessary to take too much power bars with you, because the food is really delicious every day!.
Thanks a lot to our guide Victor, the cook and the porters, they all did a really good job!!!.