For all those eager advocates of SPD clips, or any other mechanical method of attaching your feet to the pedals, here's something few of the clip using fraturnity rarely tell you. Unless you aquaint yourself at an early stage in your cycling life and feel very comfortable getting in and out of clips at split-second notice without having time to think you might end up as I did a few years back, running out of momentum on a steep hill and quite suddenly face down on the black-top.
I think most people would say it is rather foolish to start any kind of major tour with new equipment that you are not completely familiar with. Sorry to hear about your troubles, but what were you thinking?
The flip side, of course, is that clipless (or even toe clips and straps) allows a cyclist with adequate low gears to spin up many grades and save his or her knees from pushing too hard, and the problems that come with that. "Attaching" feet to pedals prevents a foot from slipping off and forcibly acquainting one's crotch with the top tube.
It boils down to a personal choice, of course. If a rider has put in some training time with bike (including pedals) before starting off on tour, either clipless or rattrap/flat pedals can get you where you're going.