Chevybruce discovers the joys of a classic GM annoyance, stuck clutch plate.
I am dismissing a disconnected or broken clutch linkage. You did check for this, right?
You are in Pennsylvania, high humidity, chances are good your clutch plate is swollen with moisture or a bit rusted here and there causing your plate to be "glued" to your flywheel. If your rear main seal or trans front seal leaks oil, could be swollen with oil which has become sticky or partially hard.
I have experienced this a handful of times over the decades, and always after a long sitting period.
For all of these cures, let your engine idle and warm up to operating temperature beforehand. Heat will help.
First cure is to set your parking brake, slip your truck into _high_ gear, clutch to the floor, key off, then stomp on the floorboard starter button. Give this a try, brake on, high gear. Be ready for your truck to lurch, be sure you will not crash into your wife and especially not her car.
Another cure is adjust up your clutch way too tight. Take out all slack and go another quarter inch to half inch. Work your clutch a bunch of times without your engine running. Slip your trans into _high_ gear, bottom out your clutch, key off, hit the starter button, see what happens. Remember to readjust your clutch play to correct settings so your throwout bearing will not spinning all the time.
An exasperating cure is to raise your rear tires off the ground, firmly and safely support your rear axle with good stands, chock your front tires. You might need a freshly charged hot battery for this. Idle your engine until well warmed up. Turn off your engine. Slip your truck into second or high, clutch in to the floorboard, start your engine. Tires will spin if your clutch plate remains stuck. Keep your clutch pressed down. Slowly apply your regular brakes, this should cause your clutch disk to release.
Should those fail, might as well drop your trans then pull the clutch out for replacement. Easy job, just a few hours.
A caution is should you hear serious clunks, clanks, any bad noises, stop what you are doing, replace the clutch.
Work safe and good luck with a well known GM annoyance!
Billyray