I listened to Colin Blunstone's One Year a couple days ago (there's a post about it from my Collection Audit project in the queue), and I noticed that the (upright) bass part in "Smokey Day" is pretty simple (it's mostly just three notes: A, G, and F). That got me thinking about the other version of "Smokey Day" - the one recorded in December 1968 in the nebulous post-Zombies/pre-Argent period. I was figuring out a lot of parts last night, so I thought I'd give that a go too (I'm not sure if I ever tried figuring it out before), and I got the opening eight measures of the guitar part.
Once the vocals start, the guitar part changes, but since it's obscured by the vocals, I haven't figured out anymore yet. This itself was hard enough to record; it took me seventeen takes, and I have a blister on my finger.