Not quite sure what you mean be front end cap?
I am assuming they are both the same wheel base?
Are both trucks the same trans type ( auto or stick )?
The cab, and bed will be a direct swap. If you have access to a backhoe, or some sort of gantry, and a chain fall it can be done with one, or two people. If not then you will need 5 or 6 people to help you lift it from one to the other. Once you have it unbolted its only a matter of an hour or so with extra help.
You have transmission, or clutch linkage to deal with, brake lines at the master cylinder, steering column at the rag joint. 4 cab mount bolts, 2 core support mount bolts, a couple ground wires, and the wire harness where it bolts to the firewall side of the fuse box / bulkhead connector. As far as the nose it can be swapped with the cab or without. If you remove it there are 2 bolts in the back of the inner fender well, 1 underneath at the front of the inner rocker, 1 behind the door above the top hinge, 1 under the hood at the rear just ahead of the windshield, and the core support mount bolts. You will need to remove the grill to get to the top side of them. Then the whole nose will come off as a unit.
There will be a plug under the rear of the bed for the tail lights, providing someone hasn't butchered it! The fuel filler tube unscrews from the bed side around the filler. You will have to swap the step side filler neck onto the other truck too.
As far as the nose, and motor wire harness they are close enough that they may interchange, but would be one less worry if you used the harness with the new cab.