Thank you so much for sharing this NMB, I'm glad to see this getting exposure! I have also read in bass guitar forums (fora?) that playing bass and singing lead at times requires 2 brains. That's what makes Randy's performance of TITTL so impressive: not only does he have to sing with emotion and hit those notes, he's playing that walking bassline as well.
He's come up with a lot of creative bass lines over the years but I love his rompin' one on Life in the Fast Lane, esp. that mini-solo on the bridge, around 2:42. This is another isolated guitar part.
https://m.youtube.com/watch?v=2AS9B2Bskig
(What a great topic for my 1000th post!)