Or just use a fat tired bike, as was often done in the 60's and 70's in Southeast Asia on very rough terrain. gear can be hung alongside the front and rear wheels, from the handlebars, and on a rear gear rack, among other points on the bike. I understand loads up to several hundred pounds were moved that way. Hand breaks (OK, who remembers coaster breaks?) can be used to help control the bike on downhills. <img src="/images/graemlins/cool.gif" alt="" />
Worse comes to worse, you can always ride the bike!