Guys I just did the "alternative rainbow mountain tour" yesterday with an agency I found online (called exploorperu) and it was absolutely amazing!! I had to friends from Cali that did the regular tour to the Vinicunca mountain last year and they complained about the 3-hour hike and severe altitude problems that they had. In this "alternative" tour you only hike for like 45 minutes and then can already see multiple rainbow mountains (not just one!). My guide's name was Roger, a local guide from Cusco, and he was awesome! Breakfast and lunch (both very good) was included. I can only recommend considering the alternative if you're planning on seeing the rainbow mountains :)
Happy travelling peepz!
