The 5 days/ 4 night trip to Machu Picchu that I did with a friend was amazing! We saw amazing landscapes and had a lot of fun with our group and our guides Carlos and Marco, who were both awesome and took really good care of our Happiness.
The second day was physically the most exhausting, but still absolutely doable even if you're not the fittest. All the other days were fine for us, but you should take shoes you can walk in comfortably for days without getting blisters.
Also strong insect repellent for day three and four because the Mosquitos will eat you alive! All in all we had an absolutely amazing trip with so many different Things to do and see and I'd recommend everybody to do a trek to Machu Picchu instead of just going by bus up to the sight.