Used Bridgeports can be rebuilt but it may cost more than what you pay for the mill. I wish that I had the room for a full size machine of any type. That is why I have Sherline machines. I have 6 of them right now that get almost daily use. A couple of them are dedicated lathes for making my bezels.
I would go look at the mill and ask to see it run if possible. Check to see how much the hand wheels move before the table moves. This will tell you how much 'slop' is in the machine.
Good luck in your dealings
