I'm a veteran Hike-Biker. Asthma nails me sometimes and there's no benefit on staying on the wheels for some of the steeper hills. I used to do it A LOT while mountain biking when all I had was a Huffy 12 speed that was geared well - if you lived in a world that was perpetually downhill in all directions. That was back in the day when suspension systems only came on the front of the bike, were a total novelty, and had all of about 1" of travel - 18 speeds were common enough, 21 speeds were like some holy grail, and if the bike was under 30 pounds you were doing well. I used to pass people by walking the bike up steep grades...moseying by people pedal standing and spinning their tires. As far as the pedicabs I've yet to see one and I walk around downtown quite a bit. I imagine if it's geared well enough the weight isn't going to matter so much, no minimum speed is required to keep them upright, but you'd better be ready to accept SLOW. 100watts can only move a heavy object up a hill so fast.