Alright, very good news to report after all the fear and frustration. I crawled underneath with flashlight in hand last night. Upon inspection it turned out that the starter drive gear was somehow jammed in the engaged position and would not allow the flywheel to turn. A large screwdriver and a little wiggling of the flywheel and it popped back into place without a problem. Of course, I then found out I was out of gas so still could not take her for a drive. Oh well, it gave me the chance to finish putting together the grill and hanging that so it looks like I have a finished truck now!
Thanks for all the advice and info. I'm glad it turned out to be so easy a fix.
