So did I, on a 93.
Get a 40+" breaker bar and a T55 driver.
Crawl underneath and SOAK the visible threads with PB Blaster or equivalent (not WD40).
Be prepared for a sore back the next day, if you aren't used to pulling in excess of 150 ft/lbs over and over again. You'll want something to rest your knees on too.
An Impact gun with 120 psi couldn't TOUCH those bed bolts. Even after I turned them out partway, the impact wouldn't do it and they don't get any easier as they come out further.
There is a disconnection point for the tail lights, right about at the center of the tailgate, so look for that. You also want a strong friend to help lift it off AFTER you remove the tailgate.
2000 2.5 MO5D 4.10 one-wheel drive DD - gave to my older son
1990 STX 87 2.9 going in.....Junked it
2000 3.0 4WD M05D 4.10 S-cab Off-Road package with 235-75-15" tires, hotrod DD, lol