The only reasonable ways to get to Machu Picchu are to either hike the famed Inca Trail or to take the train. We took the train. The Inca Trail system is vast and covers most of Peru, Bolivia, Ecuador, Chile, etc. But the trail modern day tourists take is the one from the Sacred Valley to Machu Picchu (33 km and four days of backpacking, climbing and camping at high altitude) or any number of shorter treks starting at several points along the way. A guide is required to hike the trail and most of the time you will also get porters, gear and have your meals prepared for you. I understand that you'll need them because the trail is tough.
If you'd like to hike the Inca Trail for a little way you can get off at the last stop before Aguas Calientes and hike the last rugged six hours or so of the trail.
We got off the train in Aguas Calientes, which is the end of the line. We were met by a representative from our travel agency and porters from our hotel. The porters took our bags and the rep walked us a short distance to the bus station. Aguas Calientes is a small town and you can walk anywhere there.
From Aguas Calientes you either have a long hike or you take the bus for a 25 minute ride up 14 steep switchbacks to Machu Picchu. The bus is also expensive, but they are convenient and save you a lot of time and energy. They were nice Mercedes Benz buses and made trips constantly back and forth all day. The photo above shows a view out of the bus window.