Hey-- it sounds like you have gotten some good news! this is great and I am really happy for you and your mother! I hope you will forgive me in advance for proceeding to specific advice based on one person's experience with MY mother; she was 83 when diagnosed with lung cancer had smoked for 50 years, and the bill came due. She took radiation only, which knocked it back, and had about 2 good years, went downhill very quickly at the end and died 2 years 2 months after original diagnosis, when tumor was originally 3 cm diamter squamous cell carcinoma.
I assume your mother to be somewhat younger than Mom was when seh found out and able to tolerate surgery,based on all those strenuous years as a dancer.
Go for the surgery. There is NO good chemo for lung cancers, and radiation only knocks it back for a time. Those are delaying actions only. Go fot the cure, and accept the quality of life willbe compromised (you won't have as much energy with only one lung working instead of two and less oxygen intake)
There may be very good reasons why this would not be the right decision for your mother-- but if she is 60 and in good health, it's worth discomfort and cutting your chest open to buy what could be another 20 good years. HMMV. For what it's worth, we are (obviously) thinking about you and your mother and hoping this story has a good outcome. Please tell her it's not hopeless unless she gives up!