can I use any of the parts??? Van

[kanuck]

I just picked up a 1989 1/2 ton van for the seats to put in my 88 1 ton work van.
The van starts and runs OK and it is in rusty but usable shape, but I can't register it for the road because of paper/inspection issues.
It has high mileage, (200,000miles) but only puffs blue on start up.
It is a 305 FI with a turbo 400 and 3.08 rearend. Wheels are steel with caps.
Are there any parts besides the motor and transmission that interchange with the pickups. I have a 1980 short step that was a l6 with a manual but has no drivetrain at the moment.
Any suspension, rearend or usable things I should keep???
Thanks