I also used a folder, back in 2012, but mine was a Dahon Mu Uno, modified to use a two-speed kick-shift hub. It happened to be a very muddy time, but I made it without any major problems. That said, all of the wet and mud was hard on the bike, especially the main hinge. I also had to replace the original pedals along the way, as they were not sealed, and the bearings got destroyed. Overall, however, it was a lot of fun... just messy.

If interested, here are some photos: http://hpscott.smugmug.com/Travel/CO-GAP-2012