I would suggest that you do both. Go to the local hospital and find out what their treatment plan will be, then go to U of M for a second opinion to make sure they concur. You will need to take copies of all his scans, etc.
Dr Kalemkarian at the U of M lung cancer clinic is excellent. Your dad's case will be reviewed by the entire discipinary team, not just him. This way, your dad is close to home for chemo treatments etc. and not running to Ann Arbor for everything, and you have the peace of mind knowing he's getting the correct treatment.
This is what we did and it worked out well. Our local cancer clinic was very interested in U of M's opinion.