Hi mate,
My 172 has done similar mileage and problems you should look out for are, like you say timing belt - ask if it has been done if not will need changing, auxiliary belt and tensioner (for the power steering air conditioning etc) , if these are worn the belt starts slipping and making an awful squealing noise, i bought mine with this problem and saved a packet because the previous owner didnt know what was wrong, it cost me about £200 to get both the timing and auxiliary belts changed. If you get to test drive it, floor it in first and second and if you hear a loud clunk that’s the engine mounts flexing and the engine bangs against the sub frame (This is an annoying but harmless problem alot of 172s suffer from this and its very difficult to cure). Main thing is the general condition, make sure its been well looked after and the usual servicing and maintenance has been done and you should be ok.