Quick tips on stopping the rust on the cheap

Best case sinario.... What I would do. If you are going to pull the engine, I would bead blast the engine compartment, and epoxy primer it, then if you want you could spray it the color you want in the epoxy window, then you wouldn't have to scuff the epoxy before top caote goes on.
You can try to remove the rust with some of those rotary flap type disc' on a electric grinder. I've never had much luck with wire wheels, it seems they just "polish" the rust.
Don't know if you have a air compressor, but they are great tools. If you don't, don't buy a small one buy the biggest you can fit in your work space, and that you can afford. A 60 gal would be the smallest I would get.
I bought a small 20 lbd sandblater from HF, and blasted the whole under side of my 66 Dart, while laying on the ground, epoxy primed it, and sprayed a single stage Urethane Red over the epoxy. Big sandblasters use LARGE quantities of air, that why i only use a 20 pounder.
The rust in you pics is not that bad looking. Thats just surface rust, looks ugly thats all.
Im no pro thats just what I would do.

Dave