If I'm parsing the language correctly at all, the refrain is two lines, 15 and 17 syllables. Rhymes are aa. The verses are 14-14-15-17, with the last two lines being sung to the same melody as the refrain. Rhymes are bbba.
Each of those lines, musically, feels like it's two parts.
The tune, as I know it, does not have that many notes! Zah? Listening to the recording isn't much of a help - they go so fast I can't make out which words they are singing, let alone to which notes. If anything, I expected melismas (several notes per syllable) in some places.
Approach taken is "good enough for folk music," at least for the first draft. I'll put a "/" in to denote where the musical break is in each line, because there's a lot of stretching and melismas going on. I'll also boldface the syllables that fall on stressed notes.
Refrain (needs work):
Ho-ly Ma-ry will suffer not / Her loy-al pil-grims be put on the spot (x2)
(Each half of the line should actually be its own line, rather than just repeating the refrain.)
There is a miracle that I'd like to / Tell you all about, listen well
('that I'd like to' is asking for rhythmic trouble)
That Holy Mary had a hand in / That's the story, as I heard tell
Nine praying pilgrims, Rocamador bound / where the monks and the nuns live in their cells
(stress on "in" isn't good form)
Simply and humbly they went over land / very simply and humbly as good Christians ought
Then in the e-ven-ing, lodgings found they / Entered town and found an inn
(Not happy with inverted word order)
Meat and bread is what they asked for / Supper ordered for all within
Wine for their drink, but then they all got up / to their rooms where they prayed to the fair Virgin
(It's Virgin, not Virgin)
To beg her, to beg her Son to attend / and to hear all their prayers and their pious thoughts
Hrm. The next two verses have five lines... what?
Also, a close translation is proving... slightly stodgy. There's too much set-up and not enough dancing pork chop. (And way too much religion for the comfort of many Scadians, although there's also an element of 'why is that my problem?' there.)
Maybe the best thing would be for me to take the overall story and rewrite it in the details, using the same tune. My very own Hollywood adaptation.