I ran for an hour yesterday - did about 11.5K. Then I walked for 11.5K.
My leg is fine now. At least I know one more weakness is sorted. So going forward, I should always ensure my knees, calves (ankles), shins and back are strong and flexible. Hamstrings are covered by running itself and the stretches. The quads will be covered by the squats and the quads cover the knees.
I have decided that since I was getting stomach cramps even when I quit the roller, I will be using the roller anyway. No looking back.
This is the year of going the distance. Weight loss, speed, strength, discipline. You name it. This is it.