I keep hearing..Install the hood 1st...before any core support( use a stick to hold it up)..get the hood to close properly( is it possiable?)..there is a cam action that takes place ie ;the hood lowers,and just before it meets the cowl..it drops down.This appears to be the tricky spot for how Everything else goes together..futile may be a good word to use,
Have someone else slowly open and close the hood ,while you watch from a couple of feet away to see the subtle drop...
You may make small incremental adjustments to get it..., or some wholesale hogging at the hinge positionto get it..Good Luck! .Don't let it beat Ya..it's just a dang old truck!