FWIW, I carry my B quite a bit while touring - up to 1/4 mile bushwhacking deeply into the woods for secluded wild camping (and back out every morning), and once even hiked up a 30 story staircase with full touring gear.
The easist way I found to carry the B long distance is to flip it upside down and rest the main tube on top of one shoulder with a pad attached to main tube - pretty much the same way you'd carry a 5gal. water cooler jug on your shoulder balancing between your head and hand (holding seat tube in the triangle). On longer portages, I extend the seat post and strap the front wheel (so it doesn't unfold) and rest the the main tube across both shoulders behind my neck - I wrap my left arm around the seat post and hold the seat to keep it in position and balanced, and sometimes right hand on the hinges to support some weight.
I used to travel a lot with my parents as a kid and was the designated porter... for stairs and longer distance portage, I guess I aways found suitcases easiet to carry on top of my shoulder.