I can't help with the overall length, but I believe the wheel base on a short bed is about 117". I have a '66 F-100 short bed and I know the WB is 115" and I believe the '67-'72 is 2" longer. A trailer with a 12' or 14' bed can be used, but loading, weight distribution and being able to open a door has to be considered. I have used 16' bed trailers in the past, and for me, that would be the minimum. I have a trailer with a 20' bed and it works great. I can load the truck where I want for weight distribution and not worry about things.