Everyone is told that you have to get to the ruins to watch the sunrise. Also one part of the ruins, Waynapicchu mountain, is restricted to 400 people per day. So by 5:15 am there is a huge crowd in the main street waiting to catch the first bus (5:30).
Waynapitcchu is the mountain in the background behind the ruins in almost all the photos ones sees of Machu Picchu.
We had planned to be with the throng at 5:15 but frankly wanted a bit of extra sleep. So we caught the more civilized, and not crowded, 6:00 am bus. The advice about the morning light was correct, the ruins look fabulous in the slanting early morning light. But we did not stop for too many photos as we walked to the entrance of the Waynapicchu trail. As luck would have it the trail had not been opened for the day when we arrived so we wound our way to the front of the crowd just in time to be some of the first through the gate. What luck - extra sleep and still we got in.
There is no way I can make words do justice to the climb up and down this mountain to the ruins at the top. The route is a path, with stone flagging and stone steps and stair ways, so it is not rough - but it is steep. Very steep, and the steepness is much more apparent on the way down when you have to look down the path to the valley floor maybe 3-4000 ft below. That's what climbers call exposure. The view of the main site and the surrounding mountains from the top was wonderful, we spent a long time on top admiring the view. As we struggled down the steep stairways we wondered how anyone could build these structures - we had trouble simply walking on them.
About mid day we left the ruins of Machu Picchu tired but satisfied with what we had seen.
We spent the remainder of our time in Agua Calientes by sampling the hot spring baths a short walk up the river from the village, watching the stone work going on in the river, having cocktails at one of the many bars, and browsing souvenir shops.
The trip back to Cusco was a combination of train and bus. The train part of the journey featured a dancing display by one of the train attendants dressed in some kind of demons costume, and a fashion parade, again by railway employees, of garments made from Alpaca wool.