I will be traveling from Puno (after visiting the lakes) to Chivay for a trek of the canyon. I'm thinking about doing a 2D/1N or 3D/2N trek. Do I need to have this per-arranged before arriving to the country or could I arrange it while in Puno? Is it possible to arrange a tour when I arrive in Chivay? I'm pretty comfortable with Spanish and don't mind taking public transport. My main concern is missing out on the opportunity to trek. What advice do you have?
Also, I'm planning to depart for Lima directly from Arequipa after the trek. What's the latest most groups get back to Arequipa? What's the latest flight I can book from Arequipa to get back for a midnight flight (from Lima) to the EE UU? Also, do I need to pre-book that?