Skip MacGuvyer- half his stuff wouldn't work in the real world and he had perfect hair, he was a cream puff. Think like Les.
Let us not forget trucks do not find themselves in the middle of the woods, an old roadbed must be nearby and that should lead to civilization.
+1 on that. Even a 50 year old logging road can be followed.
-Glass from the windows, as cutting tools.
-If it is that rotted out, the battery is probably dead, but worth a shot.
-The seat belts, if it has any, might still be decent as webbing.
-Wires, all you can reach
-Mirrors for, well, mirrors.
-Any fuel has long since turned to goo or evaporated off entirely, but the oil pan might still have an ounce or two of usable tar in it.
-Hose clamps
-Hub caps
-Depending on the type of reflector in the headlight, they might work as a parabolic fire starter
-Tires, hosing, inner tubes- fuel, smoke signal. If inner tubes still intact, float for gear (or you), or cut open with one end then heat sealed to serve as the nastiest water bag you'll ever use
-Depending on age, it might have never had glycol in the antifreeze, just water and alcohol- water vessel from the over flow container, and from the wiper fluid container.
-Search under the seat and in the back for old bottles and cans
-If the upholstry is raggedy but mostly intact, use it as part of a shelter or as a pack
-examine door and hood releases- might be usable as spear heads with grinding, as might other parts
-turn signal switch, lights, et al from the steering column, for use as a trap triggers
-beat on stuffing, then pull it out- this old, it will have been used as a nest, someone might be home. At the very least, you get mouse nests
-if possible, exhaust pipe, to use as chimney in pit fire or to use as part of shelter (assuming you fit under there)
-fuel line, either as kindling if it synthetic, or as light copper tubing that can be rinsed well
-wheel weights, as weights for various reasons- leave them if you can't find a good use for them immediately, too heavy
-tail lights, even without internal light they still would reflect red past the usable range of a searchlight at night
-since it probably has a bench seat, the heavy wires under the stuffing of the seat, to be straightened and used as needed
-floor mats, if intact, to be used as burnable rubber and/or trevois padding
-accelerator, throttle, break and clutch cables, with the pins, very strong
-fan, blades can be broken off and sharpened easily for use as scrapers or blades
-air filter housing, to use as firebowl
-is the tire iron still there?
-hood, can be used to form travois, part of shelter, or for other purposes
-wheels, remove and use with a tree for an axle to convert travois into cart
Parts you can't really get to or get into with these tools-
-fuel tank, remove and CAREFULLY burn out, turn into stove
-a number of gaskets in the engine that are undoubtedly rubber that the oil is still soaked into
-if it has one, the catalytic converter- the platinum is top notch salvage right now.
And always, check the glove compartment. You never know what you might find.