Family '64 4-door Valiant winter re-do

I moved back to California, and I've spent most of the last year working on the motor. It's finally time to start back on the body.

Last weekend I pulled the motor and front clip, so that I could prep the engine compartment for paint.

I'm not sure what the best approach to this is. The original paint is not in terrible shape, just dirty, but there are a number of spots with bad paint and some surface rust.

In an ideal world I would have the car sandblasted but I'm trying to do this on a budget and I want to preserve the original interior paint.