When you arrive to MP from the Inca Trail you are exhilarated but tired. You usually then have to do a guided tour with your guide and the group for about most of that morning and day, and it will get very, very crowed. After the tour, you can then elect to stay at MP until closing time, or you can go down to Aguas Calientes and then come back to MP in the afternoon and stay until closing time. If you're not too exhausted then you can see a large chunk of MP on that one day.

If you really want to climb Huana Picchu, the it's probably best to come back early the next morning so that you can get your ticket stamped to allow you to climb. However, one person on my Inca Trail trip did elect to skip the guided tour the day that we arrived at MP and climbed HP because there were still tickets available to climb it. If you really want to do this then make sure to tell your guide(s), so that maybe he can try to get ticket for you, but it's not a guarantee though, especially in the high travel season of the summer.

It comes down to how bad you want to climb HP? You can still catch an early afternoon train the next morning back to Ollantay/Cusco so I don't think it'll cut that much off the rest of your trip.

I will admit that I visited MP on 3 different days ... and for me, it still wasn't enough, and I was there for practically from 6 until closing time for two of those days. But I'm kind of odd anyway, LOL. I think for the majority of people though 1-1.5 days is enough.

For you hike:
. bring a flashlight you can wear on your head. You'll be glad you have one when you have to use the bathroom.
. pack as little as possible.

I've done both, but on different trips. After four exhilirating but tiring days on the Inca Trail (as Axel says above), I wouldn't have wanted to climb Huayna Picchu, but maybe you'll still have tons of energy. They allow 400 people a day into the Huayna Picchu section. You have to enter before 1 p.m. and be out by 4 p.m. During the high season, they usually reach 400 way before 1 p.m.

I've been to MP several times and know that I'll probably go back several times (all work related), so I have the luxury of knowing if I don't do something on one trip, there will be a future trip to do it. For most people, it's a once-in-a-lifetime trip, so if you want to make the climb on the same day, go for it. Let your tour company know, as Axel said above, and sound them out about the feasibility of being one of the 400.

Axel2DP:
Tell me about the bathrooms at Machu Picchu. I'm one of those people who has to go a lot, especially if I'm drinking water. I was wondering if there even were any or did you just go behind a bush or tree.

The only bathrooms are at the entrance. It costs S./1 and you take the toilet paper from the attendant before going in- so you might want to carry some with you as well. There aren't many trees or bushes to go behind for females. By the time we saw all of MP then got to the entrance of Waynapicchu around 10:30 I didn't have the energy to walk all the way to the entrance and then back before hiking up Waynapicchu.

We spent just one day there, from 6:30-3:30, and saw everything except the sungate (only because I was exhausted). We took the bus so I don't know coming off the trail if you would be one of the first 400 for Waynapicchu. I was on the first bus up to the Citadel, but because there were so many people that hiked from Aguas Calientes to MP that day I ended up being #281 for the 10:00 group.

Hi susiesan,

Like nonohina mentioned, the only bathrooms are just outside of the entrance, where the bus from A.C. drops and picks up the passengers. Your one-day ticket allows you to go in and out of the entrance as often as you like for that same day. I guess I was lucky not to need to take a bathroom break once I was inside the compound; I think it would be hard to find a private place inside the compound to pee. There are trees and bushes along the Huana Picchu and Macchu Picchu Mountain trails, but they're growing on the side of the mountain.