thats what difines if a car was painted cheap or done right. if you want to leave the front clip on and not take it off to paint the jams you can paint the inside of the fenders, firewall and such now. use a flat or trim black or even satin spray paint, something of decent quality. Paint it before though so you dont overspray onto your new paint job! I personally like a black enine compartment, unless you do a frame off or some serious effort painting the firewall and fenders and getting the paint to stay on can be a challange..I hate looking at painted engine bays and look at all the flaked of chipped off paint and you see the original color behind it..same goes for door and fender jams. Do it right and you will be happy you did.
When he paints it, you open the hood and tape it off on the flat inside enge of the fender. Tape and plastic off the rest then shoot. He should also know to shoot the jams and such 1st.
for the interior pull the carpet and pin it back and paint up to the door sills or the lip the weatherstripping is sitting on. pull the weather strip too! tape off the interior really well with the right tape. using the right tape will make untaping the truck a breeze and leave no residue or try to lift the paint. Every edge you tape off, say around the windshield is one more area for dirt, or junk to get under or the paint to not stick..it would suck to have the paint lift after 6 months!
just spend alot of time on prep, he should know the paint part, but alot of the finsished results rely soly on the prep!