If you are not sporty or healthy enough to take the Inca Trail to Machu Pichhu (just like me), take the Vista Dome train to Aquas Calientes! It is totally worth it.
You might think it is too expensive for a two hour train ride. But the scenery along the rail is surely not to be missed.
Taking one way is actually enough because the second time would not be as pleasing as the first time. But i am not sure if you can buy a one way ticket.