I plan on 1 week to get Peru permits and that's either using an agent or through the folks in the office at an established Peruvian flight school. If you're doing the permits on your own it may take even longer, but I've never done them myself so I'm not sure.
Guayaquil is a good stop. There's a lot of General Aviation there, you'll have no trouble getting in and out. Avgas was about $6.70 / gal last time I was there, which is about average for this area. Ecuador landing permits are easy.
I'm always IFR, not sure where you can get VFR charts for Peru.
The AIP lists Talara as international airport, jet fuel, no avgas. Email is Aeropuerto DOT deTalara AT adp DOT com DOT pe.
Sorry if I'm stating the obvious but don't forget your orange fluorescent jacket, most airports here are kind of serious about that and it will help getting through the airports quicker if you look the part of a pilot.
Enjoy the ceviche and pisco sour
