Pay the coin for the trans rebuild then sell the Satellite to finance the rebuild of your high school truck.
Easy for me to say but since you asked...
The trans guy may not know how easy it is to find an AD truck. Surely he could get another. But not for the cost of his own labor (free-as in no cash out of pocket) not likely. That deal really is "good as gold".
The picture is really small but I'm guessing that it's worth more than 300-500 dollars.

You lost the truck once when it was in the junkyard and you've been given a second chance.

Unless you really don't mind, then it's a good deal, you get a trans in trade for an old truck thats just sitting on your dad's land. Everyone's happy.
You already have one old AD - why do you need two?

I'm just rambling, trying to cover every side of the argument.
Best of luck with your final decision.

Gravity - It's not just a good idea, it's the law.