I finally got the results back from the half-marathon I ran last Saturday, so I could compare them with the results from the half-marathon I ran a month ago, and I'm somewhat pleased: I "ran" (jogged - walked - stumbled - and - yes - did - a - little - running - too) the second one in about 5-1/2 minutes less time than the first one.
This progress is not huge, not as big as I'd hoped for. But it's something. And even more: My knees didn't start killing me until the 10th mile. Now that's progress!
I'll keep training, of course, and even though these running events have really been training for the cycling events, I'll run my next half-marathon in August, and hope to cut more than another 5 minutes off my time then.