Bus up the hill to MP-15 min, hiking the Inka trail-3 days. As other posters suggested, there is a possibility of altitude sickness. My most recent trip was with a friend who got dreadfully ill. Oxygen every 15 minutes, coca tea, nothing helped. Finally a doctor came, administered a few injections, and by the morning all was well. Noone knows how they are going to react to the altitude. Cusco is higher than MP so if altitude is a problem it would be better to stay in Aguas Calientes (at the base of MP), and spend less time in Cusco. There are many little hostels very reasonably priced in Aguas Calientes. You can get the first bus up the hill to watch the sun rise over MP.