The Trek i have I measured and it 61cm, it does not have Canti, brakes, apparently the 614 bike which is a 531 tubed bike is a good candidate for a 650 conversion, i beleive this to mean the spacing for bigger tires is quite good.
It has a rack mounted on the back.
its a 531 bike so it is a lugged steel frame.
i haven't measured the rear spacing but i would imagine its 126mm as its from 1982.