Nu, pick a date!
Have you been out there yet?
I'd also be game for a Machu Picchu Photo DO
Never been out there, but had a photography trip (Antelope Canyon, Havasu Falls, Monument Valley, and Bryce/Zion/Arches) semi-formed at one point which didn't work out.
I'm absolutely game, but I don't believe I could get away from work before Sukkos. That should around foliage time IINM.
Machu Picchu never really interested me photographically. Walking for two days to take a picture identical to millions of others? Meh.