I wasn’t on TR back then, I just started with 4 to 5 weeks ago.
Besides doing the exercises with my physio, everyday I did 3x30sec wall sits, 3x20 seconds hamstring stretches and 1x10 of ‘overstretching’ my leg while seated/lying down so that you feel your upper leg tense up.
As what I was allowed to do in terms of sports, I was allowed to cycle but not with any power, so that meant light gearing and high cadance but if my knee acted up I had to lower the intensity.
I commute (10 mins max) to work every day on a regular city bike and there is a small incline in my route, so I got to test my knee twice everyday on the progress.
I had to be really mindful about what kind of force I was putting on my knee while riding my bike, for instance at a traffic light I had to make sure that I would use my ‘good’ knee for the initial force to get me rolling again.
You might be better of just following loose workouts like petit, bald knob and brasstown with a lower amount of power. They will keep you active but will not be so power demanding for your knee.