solfege for "Going Down the Valley"

Yesterday's concert was great fun.  Here is the YouTube of the beginning of the concert.  There are several things you can listen for as you watch the first song.  First, as you listen to the first part (the chorus) see if you can pick out the melody from the four parts that are being sung.  Next, as you listen to the verse (sung in unison) see if you can figure out the solfege to the first phrase.  It starts and ends on "do" and only uses drmf.  It uses mostly stepwise motion.  The words begin "We are going down the valley one by one..."  If all of that seems like way too much work, just watch the video and enjoy.