I bailed on the plan to swim this morning. I slept in instead. My calf is still cramped, though better. About all I can say is that in the morning walking wasn't actively painful. Linda massaged it for a while, and I blasted at it with the shower nozzle. Later we went for a gentle walk down to Fish Creek. The pain gradually went away, and for a while it didn't bother me at all. Toward the end it started coming back again, and I was pretty glad to sit down.
However, we walked to the base of what I remember being a very steep hill that might be good for run and bike training. Here's a couple photos of it, though they don't really give a true impression of how steep it is. It keeps going up after the corner you can see. At some point I'll have to try riding up and see how far I get, and if I can get my feet unclipped quick enough when I stop.