How to realign a cab?

[ryans69chevy]

I've been thinking a lot about my cab and how I can fix it. Back in high school I bought this truck and fixed a lot of the cab, but I did it in a poor manor. I left the cab on the frame and starting cutting out the front floor pans, rockers, cab corners, and front and rear cab supports. I did all this at once without bracing the cab! Pretty stupid huh? It's actually not as bad as you would think with the amount of work I did and how it actually all fit back together.

The biggest issue is the door alignment which the drivers door needs a bit of a slam for it to close all the way. I did bring it to a body shop and they did there best with the work I did. They got it pretty good, but now that I'm doing a whole rebuild on my pickup I really need to fix this problem which I know it gonna require me to take out a couple panels if not all of them.

So I'm wondering where do I start? I know I messed up and did not do my research before I dug into this rather large project. What steps do I need to take to make it worthy of hopefully a show truck.

Thanks for any advice and opinions. I'll post pics.