I took lots of small rest breaks and trained the dog to sit (with treats I brought along), which seemed to help me get through OK. I wasn't fast but it wasn't awful either. Of course, I have a half marathon entry for this Saturday, and I would not have been able to racewalk that this morning. I have decided if I feel suspect on Saturday that I will walk it slowly with Diane, and stop at my house (at the 8.5 mile point) if I feel too tired to finish.
Anyway, this morning I did my walk at 6:39/km pace in 39:56. Slow, sore, a bit tired, but done. I have some residual soreness now (at 3 pm) but really not bad at all. Hoping I will feel better on Saturday.
Garmin data here.