[87 V20 Scottsdale]

I've seen them with 4x4 front ends. They're usually off road utility trucks or fire engines. I don't think that they were actually considered K60 or K65 though. The fiberglass tilt hood was an option beginning in the mid-70s, but were more common in the 80's. Registration and insurance would depend partly on what kind of plates you would be running.

Putting a C60 doghouse onto a light duty pickup would be quite a chore. First off the front axle on a pickup is narrower than on medium duty trucks, so your wheel openings would look strange with the tires way back inside them. Then you'd have to address the fact that the medium duty trucks have a shorter hood than pickup trucks do.