Peru is very anti drugs from a legal perspective. However the structure of its society is not like that of Europe, where the infrastructure of law and order are more comprehensive. What I mean to say is that especially in more rural areas, it feels fairly safe for 'gringos' to get high there within reason. The most risky business is scoring a bag of weed for example(you might get set up in a scam by a dealer and a crooked cop). Once you've got your smokes, as long as you don't go toking in the Place DeL'Armas on parade day, you are probably not going to have any bother. As for 2CE, a 20mg dose in a cigarette paper looks like a bit of waste paper in an emmergency. And besides, the cops out there are mostly interested in keeping tourists safe, tourism being an important income to Peru.
It would be obviously bad to get busted, but the place seems fairly laid back in the main if you are sensible.
I reckon a month is overstating the gap you need between an Ayahuasca experience and use of 2C's. My only experience in this department was using 2CB a couple of days after a pharmahuasca on 300mg Moclobemide. There was no qualitative difference to the 2CB as far as I could tell. However natural sources of MAOI may have a longer duration of effect than Mocl.
I really would have loved 15mgs of 2CB onboard when I went to Machu Pichu. I did sneak a couple of joints where the crowds of vistors had thinned, and watched the mists decend over the fantastic vista of walls and parapets.
Peace - Pipp