anything's do-able Greg, but I don't think it'd be easy - don't have a 60's truck right now, but I remember those cabs being bigger than the TF - it's tough enuff to get all the sheetmetal to line up proper and look good on the frame that was designed for it - look at the diff twixt the rad supports on the 2 frames - that's what makes the whole front stay where it belongs, and you'd be fabricating that setup as well as cab mounts [beds are pretty close to the same] - check the position and angles of the steering boxes and columns too - would the column be the right angle and length to mount to the dash? and how about master cyl? the only plus about that swap would be the price of the chassis, but that'd be eaten up with all the rigging required to make it work
can't imagine 1 year difference would be very noticeable in ride and handling - my 62,63,66 weren't all that different from the 57 & 58 I have now, except I think the 58 can handle a load better than any of the 60s ones - nothing wrong w/ strait axles, the TF front end is great if it's all in good shape, and if ya want it 'softer', take out a leaf or even get good monoleafs, and good radials make a world of difference - if ya want a 'car ride' think about MII or such
Bill