I second that trip, we did the same thing plus a 3 day Amazon Add on. We noticed that we kept seeing a group of people everywhere we went that were not on the tour, but were following a very similar path and schedule. I chatted with one of the girls and she was the organizer. She had independently researched and booked everything over about 6 months for her and her friends. I asked what their cost per person was compared to the tour. They had saved about $150pp. To me, just going on the G-Adventures site and picking a trip in less then an hour is worth that $150pp.
I am not a tour person, but the 10-11 day tour covered off the must do's, wasn't so painful and we met some great people. They also guaranteed a smaller Inca Trail hiking group then a lot of other guides/companies (We saw groups up to 25-30 people - We had 8). After our tour we spent another 25 days cruising around Peru on local buses which was awesome.
Edit:
This was the one we did - Costs have gone up a bit.
https://www.gadventures.com/trips/am...5/?ref=upgrade