I highly recommend Peru to vacationers if you’re willing to fly domestically. Longer-term travelers can easily spend a month or two exploring.
Although it’s no one’s travel dream to spend a night being jostled around on a bus, we’ve found it kills a few birds with one stone: it’s a great way to cover some serious ground (at least 10 hours of travel), get (some) sleep, and avoid paying for a night at a hostel.
Before we cross a border, Andrea and I always take at least a few hours to get our bearings and plan for the next country. We do research online, but also rely on word of mouth.