Yeah, no doubt.

Well, the frame is still on the truck and will not be seperated. How about the oil spray? Anyone ever had that done?

Anyone ever has a sandblast with the body still on the truck? I'm thinking they just to the easy to get to exposed sections...

 

If you sandblast with the body on, you won't get to anything that need the attention the most...mounting points and so on. Not worth it.

Oil sprays and undercoatings work well when everything is new, but all you'd be doing is covering the rust, which won't help anything.

Blast/grind it all off, coat it with POR15 or something similar.