The fact that there are hacked over frame swap projects at every swap meet is the evidence of how difficult they are.
Yes, people don't get the whole steering geomotry thing, that does get you into the advanced fabrication class.
But even putting all that aside. You set up the car to riding height, you splice the frame in and using an angle finder you set the control arms at the proper angle to allow for stock like alignment capibilities. Or outside of stock for that matter, personally it makes sense to set it up to be able to align it just as the car the clip came from. You weld the clip on at that point. THIS is a huge undertaking for you average home hobbiest.
But this is only the begining! Now you have inner fenders to cut up, you have a rad support to modify, most likely installing a whole new rad (cross flow). You then have bumper brackets, and this is before you get to the steering column.
Now, trimming inner fenders or the rad support isn't that big of a deal when you can put a template up against it and trim it, big deal Brian, but when one can't put that template because you have MANY things hitting, all over the place. How much do you trim one when you can't put it into place to figure it out because it's hitting four other places?
This gets very complicated and hard to figure out so one usually end up over trimming stuff, just cutting the living hell out of it. Often they WAY under estimate how much needs to be trimmed and trim and trim and trim until the sheetmetal fits into place and it is a hacked over mess. This is AFTER all the work in setting up the suspension geomotry correctly!
Now this is on a front clip, multiply those headaches by TEN at least.
Can it be done, hell yes. Can it be done by a home hobbiest, hell yes. With enough time and planning hell yes! One small step at a time just like anything else on these cars I have a lot of faith in the home hobbiest I have way too much respect for their ingenuity to think they can't. But looking at the odds, what would work out better, then pulling off the frame swap or bolting and welding on the great kits that are available that come with instructions (thought I admit many are pretty basic "install in place and weld".
I say for the average non pro builder it is better to take one step at a time and do the rear, that is as simple as you can get. Then move to the front and do that with the body and front sheet metal on the truck you can see exactly what you are doing and it is just by the odds going to be much nicer.