Screw that... My S-10 pulled a 95 AWD Talon from Chicago to Winona with ease and I only have a 4cyl. The car and trailer weighted twice as much as the truck did. Didnt have any problems accelerating or braking so with a 4.3l V6 you should be just fine. Although if the truck is an auto you have a chance at the tranny going out pulling that much weight. If it is, I wouldnt pull that car up the mountains, just to be on the safe side.
Good luck man. Hope the trip goes well!