Actually, you'd be much better off acclimatizing at the Tambo del Inka in the Sacred Valley. Urubamba is at 3048 meters, while Cusco is 3326, a substantial difference. Machu Picchu is even lower (counter-intuitive if you've never been to Peru) at 2430 meters. Many people who make Cusco their first stop in Peru (after connecting in Lima) suffer from altitude sickness, while those who head directly from Cusco to the Sacred Valley generally have fewer problems.