Hey Scott.
Thanks for noticing that line. Believe it or not, that was one of the last lines to arrive. Brenda and I tried heaps of possibilities but none of them seemed to sit as well as we wanted them to. When "grab some wishes" came along, it seemed to do the job nicely.
Also, there's nothing wrong with I IV V (and ii). In fact, what I've done is simply to dress up those chords and use the same progressions in a couple of keys. BIAB makes it easy and fun!
Best regards,
Noel