It doesn't matter where in Peru one is headed, all flights into the country from outside South America go to Lima.  The most common stop in the United States before leaving for Peru is Miami, but there are also many flights to Lima from Atlanta.

No matter how you enter the country, you will need a passport.  However, it is no problem to enter Peru without a visa first if you are visiting as a tourist.  They just rubber-stamp the visa onto your passport.  They will also give you an exit ticket, keep this with your passport, because you will need this when you get ready to go home.  A visitors visa is good for up to three months, but can be renewed in Peru one month at a time for up to three months more.