Coming back from pneumonia is challenging. The antibiotics will make you feel better fast but your lungs will be sensitive. Strength training should be OK once done with the meds. Start also some easy walks at low HR. These will act as maintenance for the aerobic work you’ve done so far. They will also allow you to feel your way back to more vigorous aerobic workouts. I suspect you can gradually get back into running and hiking within 2 weeks of finishing meds.