Hi Road fan -
and thank you for your rather comprehensive post: I am going to try to rule out the fork steerer tube before proceeding with a deep dive into frame alignment (beyond what the LBS did) - but I think your little treatise gives me an undertanding at least, of what I'm looking for.
Not sure I'm ready to take the TREK out to to Kenilworth Il just yet - but I think I will give them a call to ask about the frame alignment option, if it comes down to it... I don't have a lot of money to spend, but this was a really good bike, and I feel like I "owe" it something, because I was not killed or permanently injured on it. (I know it's silly of me to personalize a bicycle. but I'm probably not alone in doing that).