I really haven't heard of any common problem developing with these tractors yet. But, new tires at 260 hours? I'd be asking about that. Look to see if engine and hydraulic oil look clean and filters have been changed (especially if HST). Check for evidence of greasing and possible repairs. Ask about maintenance and repair history. Run it through its paces and check every gear, knob, switch, and dohicky you can lay your hands on. At 260 hours everything should look, sound, and feel right as rain.
With a motivated seller that knows they are getting out of the tractor biz, I'd be fishing for his bottom. I checked with my dealer on upgrading my 2010 CT335 recently and was offered a trade in value that equalled 50% of Bobcat's Build and Quote "configured price" from the website. Using my experience for comparison I'd expect his trade in value to be about 19,500 here in my area. I wouldn't feel bad about making an offer anywhere above that because I'd likely be offering more than his dealer would. But seeing you're from Canada I would expect these numbers to run slightly higher.