With Triona's fast singing to the background of Bothy Band's multiinstrumental accompaniment this task would have been too difficult for me had I not found a very close printed version in Cathal O Boyle's 'Songs of the County Down'. It is titled 'Newry Town' in that book and the data of origin is given as 1840.
Mary LaMarca's verses are pretty close to the singing of the Bothy Band and it is not worth trying to correct the odd word and in this process perhaps introducing new mistakes. Below you'll find La Marca's version with my changes in bold. When I wasn't sure what Triona actually was singing I have used the respective line from 'Songs of the County Down'.

Wolfgang

PRETTY PEG

When Pretty Peg walked down the street
Some fresh fish for to buy
The wee town clark followed after her
And he kissed her by and by.

With my tiddy right faladiddle daddy, etc.

Oh, how can I get to your chamber, love,
How can I get to your bed
When your daddy goes to bed at night
With a keen eye on his head.

Oh, go and get a ladder, love
Of thirty steps and three
And a creel all on the top of that
And come down in the lum to me

(Creel = a large basket; lum = chimney)

I went and bought a ladder, love,
Of thirty steps and three
And a creel on the top of that
And came down in the lum to thee.

No peace nor ease could the old wife get
With dreams running through her head
"I'll lay on me life, said the gay old wife,
There's a boy in our daughter's bed!"

Then up the stairs the old man crept
And into the room did steal.
Silence reigned where the daughter slept
And he never twigged the creel.

"My curse attend thee Father,
What brought ye up so soon?
To put me through my evening prayers,
And I just lying down."

He's gone back to his gay old wife,
He's gone back to she
"She's got the prayer book in her hand
And she'd prayin' for you and me."

No peace nor ease could the old wife get
Til she's gone up to see
She came on a stumbling block
And into the creel went she.

Oh, high I rocked her, didn't I rock her
Didn't I rock her well?
For if any old dame begrudge me her daughter,
I'll rock her into hell