twodeadpoets, I called the touring store and left a message with Wayne to add the backpack attachment to my order. I figure I can use one of those and something like the bag arctos suggested to sling the other bag over my shoulder, unless the shoulder strap that comes with the Ortlieb rear roller is wider and more comfy than I think it is. (Or I can get a strap pad.)

Machka, you make a good point about upper body strength. I have upper body strength but not endurance. I can carry my MTB with two loaded panniers and a trunk rack up a flight of stairs but I'm not good for all that much after. Stairs are my nemesis, and I encounter them more than I'd like when on tour. Trains, subway stations, parks... bleah. Maybe I need to do stair-climbing training on my days off the bike. (Wow, that sounds dull.)