Weeds,
I've done it both ways and completely agree with Tim.
If everything is now apart, I think you are safer putting it back together in pieces. This way, it is MUCH easier to reach inside the inner fenders without the fenders being in the way. And, you will not have to worry about scratching the finish on the top surface of the fenders as you lean over them to deal with things in the engine compartment. Offer a friend a few beers to help you when you finally attach the fenders and grill (you can easily put the other parts on without assistance).
The times I have dealt with the whole "font clip" as a unit (the grill was first removed) was when removing it from the truck and then reinstalling it (I did this last summer with my Suburban). I had one helper for the removal and two helpers for the re-installation. I thought there would have been a greater risk of chipping/scratching paint by removing the "front clip" piece-by-piece and later installing the "front clip" piece-by-piece. Also, all my wiring, plumbing, and mechanical linkages were in-place and adjusted.
Tim
