Cuzco and the Sacred Valley (the Urubamba River Valley) are two wonderful places you should visit in your trip to Cuzco. Cuzco and the Sacred Valley probably deserve weeks of attention rather than a single or two days. These are two enchanting locations whose unexpected beauty startled us. They are more than just afterthoughts on a visit to Machu Picchu.
If you want to avoid problems with altitude sickness, you can try to arrive Cusco and descended soon after visiting the famous Inca temple at Sachsayhuaman. Then you can spend two days in the Sacred Valley (9000ft/2400m), visit Machu Picchu (at 8000ft/2000m) for three days, then return to the higher altitudes of Cuzco (10500ft/2900m) which deserves a visit on the vibrant colonial capital. Combined with some diamox and the appropriate rest, you can enjoy your stay in Cuzco and Machu Picchu warded off the ill affects of a quick trip to high altitude.