Either you have something sucking the power from battery while it sits or it's a bad battery. If it sat for 10 years and you didn't replace the battery, maybe try and replace it. Wish I had a battery last 10 years. Batteries have guarantees and if you don't need it, bring it back for a refund. Sounds like there is a problem intermittent with the battery. The post on batteries can disconnect inside the battery, yet sometimes show that they are connected, with the slightest movement. Is the battery bulging on the sides a little? Batteries can take a charge and loose the charge quickly if bad also. Sure sounds like the battery to me.
Do you have a volt meter in the truck or Amp meter? Check if your recharging when truck is running correctly. For something to kill a (you say a good battery) in 24 hours, it should show up on a meter that something is grounding to the frame or turned on. Just a radio on for 5-8 hours can drain a battery.
Are you hearing a click click click when trying to restart? any noise from engine? Makes ya wonder why they parked it in a barn so long. With all these trucks being found in barns and old garages makes me want to start doing a farm to farm search for trucks.

and.... Welcome to the MightyRam50.net forum BigRam50