I love this truck, I lived in a farming community for most of my life and many friends are farmers. For anyone asking why 2 wheel drive, if you need 4 wheel drive that truck should not be in the field it is too wet and ruts are not good because of the compaction of the soil in the field.
If you take the cab that is getting bad spots and scrap out the soft uncured resin spots you may be able to wash the resin with acetone carefully to remove the soft resin remains.
If you think a 78 square body cab would work I have a built up here you can have. Unless this is an older truck. Just chop off the front?