To be honest, for a 'working tractor finish', you could probably leave the sheet metal on it, and start sanding / buffing the heck out of it whenever you get free time. If you expose some metal, it may get some powder rust on it from day to day.. but a scotchbright buff pad on a drill or buffer removes it quickly.. and leaves a nice finish.
Sand it down, wipe it with a tack cloth, mask it with newspaper and tape, and prime it with the metal still on the tractor... rattle can primer will be fine.. just remember, side to side spray motions, and release the valver between each spray motion... takes a bit longer.. but you can make a nice finish with a rattle can if you have a steady hand, and good environmental conditions.
Sand the primer down with 600 or 800 after it dries ( rattle can paint dries fast!.. but don't paint when it is hot... solvent will boil and leave bubbles.
After that final buff, tack cloth it again, and rattle can paint it with appropriate paint.... ford and tsc both carry equivalent tractor paint colors in both rattle can and bulk cans.
If you get the sanding done on say a saturday, if you get up sunday, and the weather is good, you can probably prime and paint it in one day. Won't be a showroom finish, but it will protect the metal , and look halfway decent.
Rattle can finish may look better than brush.. just depends on your hand and eye.... rattlecan may dry a bit faster too.
The frame will be easier.. just wire brush it to get loose paint off, then hit it with a couple good coats.... the undercarriage takes a lot of abuse, and isn't under the same scrutiny as the sheetmetal.
Heck.. after it cures good.. hit it with some cheap buff on style car wax.... it will look cherry the first time it rains!
I'm not trying for a show room finish either. Just something fairly easy on the eyes, and that will protect the 50 year old metal.
Soundguy