The only way you are going to get any real money for it is to fix the engine(rebuild/replace) for about $500. If you don't want to do the work and simply want it gone, $500-1000 is about all you can really expect to get for it.

More than tread lightly. Leave it like you were never there, nor anyone else.
'90 X-cab 4.88's 33 BFG AT's, rr ARB, Headers, Ignition upgrade, cold air induction.
'91 X-cab 5.29's 315's BFG MT's, rr ARB, custom bumper and flatbed