Some people will like the security of having everything arranged before they leave home. That is great, no worries while on vacation. Unfortunatly, this will cost a lot more than arranging things from Cuzco.
Don't worry too much about the language barrier, if the first place you go doesn't have somebody that speaks English, move on. Most of the tours will be priced similarly. It all depends on how much you want to carry, and how good you want to eat. Prices are seasonal too.
If you don't get bombarded at the airport when you land, then tour vendors can be found handbilling in the plaza.
Ask for an English speaking guide (unless your main language is Spanish). The two guys from Peru in our group had a hard time, since our guide spoke English well. Even if your guide doesn't know much at least you'll be able to understand. If you ask for things you will usually get them .
Ask to have porters carry camp gear and food. You don't want to carry more than your own clothes and sleeping bag. If you want you can have a porter carry everything for you.
Ask where you start from. Km 88 is good, but a minibus to a spot closer to Cuzco is better. The trail has many heads.
Ask if your price includes the bus down from Macchu Picchu. After four days of hiking you deserve to sit down on a soot spouting diesel bus into town. It's a very steep walk straight down, besides you'll want to see how they get those big busses down the zigzagging one lane road without running head-on into oncoming busses of the same sort.
Ask if your price includes the train trip back. YOu don't want to get stuck trying to deal for tickets in Aguas Calientes. The language barrier rises noticably here.
Ask if the train trip is the local or the express. You will pay more for the express, which will get you back to Cuzco in under 2 hours (gods willing). I took the local, with stops very frequent. This is the train to be on if you have the time. You are less likely to get ripped off, so you can relax. Local kids will walk up and down the aisle selling fruit, candy, Agua sin gas, jugo de pomme, and other goodies.
This train will drop you off right where the market is held, but it will probably be late at night and you will not have your wits about you. Take a cab to a pre-arranged accomodation, if it's not included.