Originally Posted by unworthy1

I think your approach with touch-up on these areas is a sound one, so do the same on the dropouts, but since the contact "faces" were once chrome plated (a very popular treatment that was misguided, IMHO) paint won't adhere well to chrome.
And the knurled surfaces of QR or track nuts will keep chewing up any paint you apply. so just mask off the DO faces and remove rust as best you can, paint all around them like you're doing. It may look janky but will do some good. An alternative to masking tape: try coating with rubber cement and let that dry, makes a sort of masking fliud. Peels off when the spray paint is dry.
Spray the insides of all tubes with a reliable rust preventative, here in the US there's the popular Frame Saver brand (most $$$) Boeshield (also $$), LPS #4 ($$) and the lowest cost plain BLO (Boiled Linseed Oil) you have to pour in cause that isn't sold in a rattlecan.
You could try posting a WTB for a good quality steel fork with the steerer length you need, not gonna be quick or easy to get one to NZ for a reasonable cost, but.... ya have to start somewhere.