We just did the whole tongue and frame on our 67 safari
It came out Great!!! Big relief to know that our foundation is protected.
I scraped like crazy with many sizes of brass or steel bristled brushes. Wear eye protection and maybe a ski mask .
I grey taped a small brush to a stick and scraped copious amounts of rust and flakes from the frame insides near the tongue.
We used the good old red rustoleum primer everywhere (taped a brush to a stick to get inside the frame areas) this was a messy but rewarding job.
I used some mettalic aluminum MAB paint that I liberated from my local municipality when they had me painting fireplugsfor a temp agency --this did Mac Daddy good job on the exposed areas of the tongue and rear frame around the black tank--also bumpers and steel parts.
I used black enamel paint for the frame then buttoned up the belly. It came out fantastic and I hope not to worry about this for another 35 years!!!!
Happy to help with any questions-- Might as well re wire your running lights while you are in there for instance. tod47d