I've got a neglected 1981 Murray SS coaster brake, and I ride up a dirt road 180' in elevation at least once daily. I still prefer it over my Diamondback 21 speed mountain bike. My maintenence schedule is before I ride, fill up the tires, hose every moving part down with PB Blaster. I never worry about mechanical failure, and I can run circles around the dept. store 21s mtns. that I ride with. I'm getting my speedo soon so I'll be able to give you some numbers, but I'm guessing I can cruise at about 15-20mph with 1-2 cases of beer strapped to me. And remember West Virginia is the mountain state; the only flat ground we have comes in 100yd long, well trimmed grassy sections.

But bottom line: try it. My friends think I'm crazy, and they might be right, but I can't go back.