I have surveyed all the versions I could find on the Internet. Here is a summary:

Variations I found in the verses posted above:

Title: LUCY LONG
CHORUS line 4: Oh, Lucy, Lucy Long
Verse 4 line 2: She hadn't much to say
Verse 5 line 1: If I had...
Verse 5 line 2: I'd whip her sure your (sic) born
Verse 5 line 3: I'd take her down to New Orleans

Additional verses found in a broadsheet at Library of Congress:

I took Miss Lucy walking, I did not mind expense,
I bought her dat ere parasol, it cost me eighteen pence.

Miss Lucy, when she trabbels, she always leaves de mark
Ob her footsteps in de gravel, you can see dem in de dark.

The world was made in six days, an' 'twas built up very strong,
But I guess it took de sebenth, to finish Lucy Long.

Lucy cuts de widgeon ping, and dances fancy reels,
Fust time I eber seen her, I cotch'd her skinnin' eels.

An additional verse found somewhere else: (I lost the citation!)

My mamma's got de tisic and my daddy got de gout.
Good morning, Mister Phisick. Does your mother know you're out?

Sheet music can be found online at:

The University of North Carolina at Chapel Hill
The Library of Congress American Memory Collection
The Lester S Levy Collection of Sheet Music