For a great analysis of the FARC peace agreement, with a lot of background, check out this detailed post by Steven Taylor at OSU's Origins site, which also includes some cool old photos.
For the October 2 vote itself, here is the really tricky part:
Between general skepticism in large parts of the populace and the uribista opposition, it is unclear how the plebiscite vote will play out. For one thing, Santos’ own approval ratings are poor, with various polls taken in July and August placing it anywhere from 20% to 29%.
In regards to the plebiscite itself, a poll from Datexco published on August 24 in the Colombian daily El Tiempo showed the Yes position at 32.1% and the No position at 29.9%, with 9.7% not having a position and another 26.9% stating they would not vote. This poll further indicated that the final tally would have Yes edging No 51.8% to 48.2% if the undecided and abstainers were removed.
One thing I keep wondering is what potential "no" voters think that vote will accomplish besides just disapproval of the FARC? Perhaps they figure it will be a sign of strength and that they're winning on the battlefield anyway. Those are dangerous assumptions.