We’ve done two treks in Peru–Machu Picchu and Cordillera Blanca/Santa Cruz. In both cases we reserved in advanced, and had really great guides and small groups (4 and 3 people respectively.)
In Machu Picchu you are required to hire both guides and porters. That provides employment for locals, and those locals are also charged with protecting the ruins and environment along the entire route.
I agree that the trails themselves are easy to follow on the Santa Cruz trek. But you may be underestimating the days’ hikes. It’s about a 3-4 hour drive from Huaraz to the trailhead, so the first day is only about six miles, and climbs from 9000 to 12000 feet through a hot and humid valley.
The second day is longer, up the same valley, and gets you up to about 13,500. We added on a mile or two to take in a side trail for views of the peaks–something we would have missed without a guide.
The first two campsites, and you are required to camp in the preexisting sites, were quite crowded and our guide and arriero did great work to get us a spot with a little privacy. We also had our own potty tent–a big deal because the established out toilets were in ruins…And there’s no option of hiking off into the woods.
The third day is ten miles, and gets over 15400 . That’s a tough day, and the last six miles were through deep mud. This was in April.
The last day was only 4 miles, but the we had a spectacular drive back to Huaraz for about Five hours.
So if you do this on your own, you need to arrange transport to and from the two trailheads, plus figure out a toilet solution for the first two days, and carry all your food and gear.
I would agree about finding a guide in advance, rather than picking someone in Huaraz after you arrive. We met groups of people who were quite unhappy with their guides, foods, and schedule. Buyer beware. Most of them had picked a low cost option after they arrived in Huaraz.
I seem to remember paying $100 a day for the whole show–transport, meals, guide, Arriero and donkeys, permits. Only extra was tips, and we were generous.
If we go to Peru again, we’d do it the same way. We are both fluent in Spanish, and we loved the conversation s we had with our guides. They were a real window into Peru. Our guide in Huaraz also worked as a journalist. Fasc