Brian, you and I hear the same stuff...I absolutely love Leave Yesterday Behind which I think gets very little credit as a long lost Carpenters recording. I also love The Rainbow Connection there is something about her vocals that really warm my heart when I hear her sing this, such a simple melody but I feel like a kid again. The vocal fry on the very last note always tears me up every time...it's my favorite part.'For All we Know' is also one of my all-time favourites. Unbeatable in almost every way, in that genre. Karen's vocal is magnificent. Her performance on the 1971 BBC concert TV show is just as good. This was the first-ever single I bought. (Actually, it was given to me, when I requested it as a birthday gift).
I have a certain fondness for 'Leave Yesterday Behind'. Fans know what it is - an out-take that probably wouldn't have been released had Karen lived. However, for what it is, I think it's still quite enjoyable and satisfying. Karen's vocal, while not top-notch, is still warm and enchanting. There's something missing in lyric, melody and structure, but I still like the song.
Rainy Days and Mondays is one of those songs that is other-worldly in every way. It has a life of its own up in the stratosphere somewhere. 'The Rainbow Connection', I think, has great charm, in the theme, lyrics, melody and Karen's reading. Personally, I really like this song and recording. I guess you can tell it's an out-take, so doesn't have the legendary status of a lot of other Carpenters songs, but I think it's still quite special.