I found it! Or rather I just stumbled across it, wasn't even looking for it, it just landed right in my lap. I mean, sure I know the song, but didn't make the connection; this is that ditty my dad would always fingerpick whenever he had his guitar in–hand.
And of all places, I found it by re–watching Intolerable Cruelty. 🤣 It's sung during the wedding scene, by the performer of the marriage ceremony, the guitar–picking and grinning "captain of the Good Ship Amore Veritas"... FATHER SCOTT.
I can NOT make this shit up! 🤣
One of the attendees at the wedding even looks dead–up like one of my dad's best friends, a guy I was just on the phone with exactly 12 hours ago! Whut tha fuck is going on?!?!
This all makes me supreeemely happy. It is too fucking awesome.
And hey, it is a lovely song, no doubt about it. I just, I had to write about this, I couldn't keep something like this to myself. It's got me me questioning reality, not whether it's real, but... it's like a Slaughterhouse Five kind of spacetime continuum–twisting moment. This many coincidences, in such pretzeled chronology...??? 
I see Lily Tomlin holding up a giant book titled Coincidences in I 🖤 Huckabees saying "They're not all significant," I reflect on the principles of randomosity and their assurance that lightning has to strike twice somewhere eventually, and I marinate in rich steamy soup of profound cosmic mystery, no matter what it's made of, I don't much care, the sauce is good. What a perfectly, comically divine singularity of a moment. Marvelous. Spectacular. My cerebral synapses sprout endless tendrils sprawling throughout the entire universe.

That whole Shangri-La's album is amazing. Hall of Fame record for me.

I don't know if you've given the recent Bootleg Series set, Through the Open Window, a chance.  It's got some good stuff, and remarkably some early stuff which has never actually been bootlegged, but there's some other things that irk me greatly, mostly about what is and isn't included.  For example, this has a selection of the so-called "Minnesota Hotel" tape (actually recorded at one of his ex-girlfriends apartment) which has been known since the very first rock bootleg, The Great White Wonder.  I have to assume that whoever curated this set already assumes that everyone has that, because two of the best performances there, "Baby Please Don't Go" and "Black Cross", are not included, even though, like, come the fuck on.  I was thinking that maybe "Baby Please Don't Go" showed up elsewhere, as maybe a free download for No Direction Home, but turns out that was a studio take.  Not nearly as gnarly and raw as this version.  And then they stuck that version on here instead!

You know what.  Fuck it.  Ima prove it.