Motor swap

So I have an 04 LB7 Chevy that the frame is rotten on. I recently purchased an 03 GMC with a blown engine and no rust. The engine is actually in the bed of the truck and the truck has a few parts robbed off of it. No ECM and TCM mainly. Of course I have those out of my original truck.
My question is, what would be the most logical and easiest way to move motors and ECMs. I have all the electronics from my original truck and I plan on swapping the ignition switch anyway. I have a bunch of locks key’d to my truck key and don’t want to pack two keys. Should I just swap everything that is VIN locked? What all is VIN locked? A new ECM isn’t out of the question as I have my current one tuned and it’s calibrated for 35” tires and I’m not going to run 35s on the new truck.