It is cleaning up pretty good. It looks like plenty of room for possibly even 28s as you mentioned. No dimples in chainstays. I would probably leave it with some narrower tires though and just have a little fun with it and probably sell it. I am in my later 60s and like my comfy sport tourers best. This will be a fun project though. I do see on eBay that the suede Selle San Marco Corsair that is on it is fairly desirable though.