When readying a car for painting (i.e. a 1987 D reg 110 pickup), which isnt in too bad a condition, already rust treated, etc. How far back to the metal to I need to take the paint before priming it, etc?

are you priming the whole car or just the areas that have had work done to them?

if the panels are already painted then you wont need to prime the whole thing, only need to prime bare metal and a small area around it to blend the primer smooth.

make sure the edges of the repair area are feathered out so there arent any ridges or edges, these will show up when the paint goes on. prime an area 2" further round the edge of the repair, then when primer is dry use 600grit wet paper to sand the primer smooth. use grey scotchbrite over the whole panel the give the paint a key, use a de-greaser all over, tack-rag all over, then paint.

So, I only need to prime where the rust is treated and it's metal, make it smooth from metal to paint so theres no obvious contour change, then prime, smooth, prime, smooth etc etc etc then paint?

Is it just going to be a toy or does it need to be smart? Are you going to be off roading it (Stupid question?)?

If it does not have to be really smart and you are off roading it, roller it on! Pikey done it and it looked quite good.. Till he rolled it! Painting it "properly" takes alot of time and really is not worth it if you are off roading it imo

All pikey did, was go done b&q get a tin of paint and roller it on. Job done! Takes a day at most, if in a couple of years it is looking worse for ware just do it again.

it's mostly to cover up the rust tbh..it'll be treated, then sanded, then it'll be a few coats of hammerite or something similar. It is going to be a toy, but i dont want it all random colours like Pikeys was before he painted it.