I struggled to find a lot of information online about other peoples preparation and experience on the Inca Trail. Sure there's comments here and there about it being the hardest thing that people have done, but nothing too useful. So here's my attempt at giving you something useful...
You cannot do the Inca Trail as an independent hiker. That said you can get a guide, so it's just you and the guide. We did it with g adventures. You can choose to do the Inca Trail as part of a larger tour of Peru or you can do it for Inca Trail only. Either way you end up in a group.
Some operators pay their porters poorly and basically skirt around the rules. Many operators don't they do the right thing. Make sure the operator you are choosing belongs to the second group, and remember porters aren't your pack horses, they are people, many older than many of the hikers, weight limits are there for their safety, don't abuse those weight limits, or hire porters outside the system i.e. along the trail.
In Australia there is no where to train at altitude, definitely not at 4,200 m! So the basis of our training was cardiovascular fitness and leg strength (for all those steps). About a year before we did the Inca Trail I had not exercised in over 4 years, so I started out slow, but for 9 months of the year our training plan was:
Monday - Rest
Tuesday - Run
Wednesday - Walk
Thursday - Run
Friday - Rest
Saturday - Cross Training - weights, cardio and stretching
Sunday - Every second Sunday we did a hike, we started off on easy 5 km, and worked towards difficult tracks of 8 to 12 km
The last month prior we had a lot of rain so I cut out the running/walk mid-week and did stair climbing in the hotel I was staying at (10 flights up, 10 flights down for 30 min total, working up to 1 hr total by the end).
We also did the Bay of Fires Walk in Tasmania in April 2011 and this gave us a great point to assess where we needed to improve or learn e.g. we started training on our Sunday walks with weights in our packs
Pack as light as possible. At the end of the hike you will smell, you will be dirty and it will be obvious at Machu Picchu who did the trail and who came on the train/bus. g adventures supplied the tents, basic sleeping mattresses (air ones were extra and worth the cost) and all food.
- Good hiking boots with ankle support are a must, it seems obvious but they should be worn i
- A good goretex jacket - keeps the wind off and keeps you dry
- Thermals - it will get cold overnight
- Gloves and beanie - I couldn't figure it out at first but I was glad I brought them
- Fleece jumper
- Fresh socks
- Hiking poles (we also rented these through g adventures)
- A cover for your pack (something I missed and used a poncho instead)
- Water container for 1.5L (I should have brought a hydration pouch for my pack)
The best advice I stole from an ex-Australian marathon runner (sorry can't remember which of the Steve's), which was along the lines of when your running a marathon and struggling to keep going, choose a point on the horizon and aim for there. That's basically what I did on day 2 (which is the toughest), going up that hill to Dead Woman's Pass I chose a point and walked to it, then stopping for a breath or a drink or simply choosing my next spot on the horizon (or the next corner).
Basically take it slow and steady at your own pace, don't rush, don't push yourself to keep up with the group, just keep going.
Enjoy the time at Dead Woman's Pass. The weather was crappy for us. It was cold, it was raining, we were tired, but I wish we had spent more time appreciating where we were.
Enjoy Machu Picchu. You walked 45km, the weather may be bad when you get there, the view from the Sun gate might be non-existent, but at the end of the day your there once, enjoy it and don't go back to town too early.