Geof, the thing to overcome this disease is to set yourself a passion and go for it. Also do any exercises at all, be it walking, (walking on a treadmill is good because you are safe indoors, no wind or rain, you can control how fast you can go - I like it that way. Others prefer the great outdoors). Yoga, Tai Chi, cycling, playing any sport even gently, anything to keep moving and breathing. You can even emb ark in learning a wind instrument like the flute (I am doing it).
Once you start, stop at any sign of breathlessness. Yet, exercise is the clue to improving your lungs and stay the progress of the disease (It's now medically proven that lung disease can be maintained and it doesn't need to go down hill).
When I had TB, I decided just that, when I go out of hospital, I'll sign up for the gym. I had oxygen bottles and a concentrator at home. Within two months, all this had gone from my house.
At first, my consultant rolled his eyes to the sky. in 2014, he said: "You are transformed!" Something to keep in mind. You too, you can be transformed with exercises.
Get the pulmonary nurse to monitor you and enrol you on Pulmonary rehabilitation.That's a lovely start. Be confident, you can do it.