Want to fix up my 1985 D150 for my Daughter!

Those old trucks are pretty reliable in stock form.
For a first vehicle I would leave it just that stock.
Get it running and driving reliably and see if she actually likes it.

My youngest daughter I gave her a 2wd Dakota, that somebody gave to me, it had a burnt valve, a bad steering rack.
I fixed the valve, steering rack, and put a new set of tires on it.
I had $325 in the whole truck.
She drove it for around another 100K miles until the trans went out of it.
She sold it to someone for $900 because he wanted the body parts.
It was rust free, and the old motor still ran.