I went with flame spraying galvanising on all frame parts and the axle housings when I teared down my Hj60 17 years ago. Then some good industrial ground paint and finish. Today not a spec of rust on the frame or axles. Even did the lower side of the body, like rockers and rear quarters.Apart from the normal paint chips ,no real damage until now.
I forgot about flame spray technology. There is very little of that in the US but would be a nice option. It is like a site sprayed powder coat (usually thermoastic polyethelyne) through a flame and melted on the part. You can coat more parts this way, including axle housings. The galvanizing part can be done with a material with zinc in it. Very cool @sved