FWIW, my Wista DX folds up with a lens on it and weighs just over 3 pounds. It folds closed with small lenses from 100mm to 240mm (Kodak Wide-Field Ektar 100mm, Nikkor-W 135mm and 150mm, Kodak Ektar f7.7 203mm, Fujinon A, 240mm).

I carry the camera and 4 lenses in a fanny pack. Of course, you will need a tripod, but a small carbon fiber job and a ball head could by strapped on the bike somewhere. You'll have to figure out where the filmholders, meter, filters, etc. go... I do bike with my kit a bit, and sometimes for long day trips, but not in real rugged country.

Best and good luck,

Doremus Scudder