[link to original on tumblr]
---&---
First, I found They Might Be Giants' Indestructible Object, which contains a cover of "Caroline, No." (I also got it just because I like TMBG.) I just listened to it, and their cover sounds pretty close to the original. I'm sure there are some differences in instrumentation though; I haven't compared them that closely (or really at all).
I also found Catch a Wave: The Rise, Fall & Redemption of the Beach Boys' Brian Wilson by Peter Ames Carlin. I have a few other books about the Beach Boys (I think this is the fourth), so I've heard of this through bibliographies and such, and I figured I would get it since I'd found it.
More tenuously related to this, I found a compilation album of the Four Freshman. Except for "Their Hearts Were Full of Spring," which the Beach Boys recorded (it's a bonus track on the Smiley Smile/Wild Honey reissue) and - if I'm not mistaken - used for the melody for "A Young Man Is Gone" on Little Deuce Coupe, none of the titles looked familiar. I might recognize one or two once I actually listen to them though. In any case, it'll be interesting to hear how they influenced Wilson's vocal arrangements. I've read that they're pretty similar.