what to look for when buying a 67-72

[grues]

I'm new here so please bear with me. I'm going to look at a 1970 swb custom that a co-worker has this week end. he has had it for a number of years with the last 3-4 setting but started regularly.My question is this what are the most rust prone areas of these trucks. what should I look for in the areas of body and frame that would be a reason to steer clear. Thanks for your time

[flyboy2610]

Check the top of the cab around the drip rail. If it's rusted out, it will be a major amount of work to repair it. It would probably be easier to swap cabs.
Under the hood, check the area where the radiator support bolts to the frame. That area is prone to rust. Replacement supports are available, but they sell for about $250.
Also look at the place where the hood hinges bolt to the inner fender apron.
Get down and check the cab mounts, and look at the bracket that the cab mount attaches to. That bracket is riveted to the frame. If it's rusted out, someone here can probably sell you some, but replacement is major surgery. Also check the rear cab mount brackets. Check the center cab support. It runs under the cab from one frame rail to the other. The ends are readily available, but the center section is something you would have to fabricate, or maybe buy from someone here.
In the cab, check the corners of the cab behind the seats. That area can be prone to rust. Check the door pillars as well. Rust out in that area usually means a cab swap.
And look down inside the cowl vent, the area in front of the windshield. Leaves and such tends to collect there, and rust can be very difficult and costly to fix.
Let us know what you find and we'll help you decide if the truck is worth it.
Good luck!

[Sharkdance]

Agreeing with everything flyboy said. But check the floor boards also.

While none of this is non-repairable, Id have to say that drip rail rust is the worst. Thats the one area that is prone to rust and causes the most work/damage/money to fix.