Well since the author didn't elaborate as to what "twinkletoe tumbleweeds" are, exactly, who can say??
Um, I liked some of John Denver's music ("Poems, Prayers and Promises" for one) but I wouldn't class him with the above-mentioned TTs as a songwriter [fair warning: I don't know enough of the former Cat Stevens' work beyond his top hits to comment on his songwriting.] Any number of Carole King's songs are as 'simple' as JD's and her output is/was prolific so by necessity some of them are going to be less than stellar. Here's a list (four, actually) for the years 1959-1969:
http://www.spectropop.com/brill/zzki...st1.html#start and
http://www.spectropop.com/brill/zzkingsonglist2.html and
http://www.spectropop.com/brill/zzkingsonglist3.html and finally
http://www.spectropop.com/brill/zzkingsonglist4.html
There are many recognizable, more that aren't, and they ain't all pearls but when she's firing on all cylinders (especially with Gerry Goffin) the music is hard to beat.