I'm still minded to be careful about my legs. It was about -15 C outside this morning, so I warmed up with some stretches inside first.
5 minute brisk walk to warm up.
7 x 4r/1w over a 5K course, trying to keep heart rate no higher than mid 130's.
5 min walk to cool down, then a few more gentle stretches.
The 5K actually took not quite 40 minutes, but I didn't start another run cycle on 35 minutes. This works out to an 8 min per K pace over all. The actual run walk segments worked out to 7:30 per K. The first couple run cycles were quite easy, with a short stride to continue warm up.
Overall it felt pretty good. I did get over 140 HR briefly as it felt natural to run a bit faster, and slowed down again, but while slowing down I had a bit of a cramp in my calf again, but not as bad. Once I slowed down it went away again, and it's been fine the rest of the day.