How to start a paint project???

[wcn8tive]

Looking for some sound advice on where or how to start a paint project. What I have is an 84, with a top coat that is going to ****, from my understanding the base primers from the factory are pretty tough and if not needed, dont sand them away. So what i am looking to find out if where do I start, as far as grit of sand paper, basically to the point of getting to the factory primer and throwing a coat or how ever many of primer...Rudy Red I heard is the way to go since I will not be able to afford a full blown paint job till I get back from the Gulf....saving it already.... But I would like to say that I had something to do with at least some part of this car getting done. Second, on door panels, at what point should i give up on trying to fix cancer rust and just replace to doors, I would rather not have to try and find new ones but if push comes to shove.... 3rd the landlau tops, remove....replace???? I kinda like the way it looks, but it seems like if it is getting to be a problem now and I replace it, it will eventually get to that point again.....
Any advice is totally apreciated...thanks for helping out a newbie...

[CDJr]

Pics of the areas would definitely help assess