This has been the big unanswered question all through my preparations, and the only way to find out was to go ahead all the way to the end. I hurt both knees running and couldn't run for a couple of years until last fall. Then I could only run less than one minute before it hurt too much. I practiced slowly during the winter and more in the spring and I'm now close to normal and can run an hour in the rough as long as I keep my knees straight. Cycling has never been much of a problem, probably because the knees are always straight, but I still haven't done long rides two days in a row. The only thing that hurts is my rear end after 4-5 hours, but yesterday was quite a bit better that previous rides.

I have a new frame of mind, which is go at the speed that is comfortable and not more. So I'm pretty slow. In the past I'd get frustrated by a strong headwind and force my way forward, making progress being most important. Now it's staying comfortable at a cadence of 75 or so which may mean 10 km/hr or less. I no longer care if I'm making progress, I know I'll eventually get to where I'm going so don't even think about it. I've discovered gratitude in being alive and really enjoy just looking at everything as I pass slowly by. The second big unknown is how it'll go in hilly country. Even as a kid I pushed my bike up some long steep hills so I expect I'll be doing a lot of that. Hopefully I'll find a comfortable slow way of doing that as well.