While travelling in Mexico, one of the most difficult times someone can have is transportation. Of course, in the tourist areas, it will be a little bit easier. English will get you to most places that you need to go.
But in the other areas of the country, where some of the most interesting and amazing places are to see, a little Spanish will be needed in order to take full advantage of all there is to offer.
So that may seem like a bummer, a huge let down. But it is not. Anybody can learn Spanish; it is actually quite easier than most think. Using some of the best language learning software is probably the best way to start the process. This will give you a well presented learning experience, and build a solid base for the foundation of the language, and the grammar.
Of course, that is only the first step. The next is to actually start speaking the language. So go, watch the Spanish television channels, go to the local Mexican restaurant and try ordering something in Spanish. Before long, you will find yourself speaking more and more.