Had no idea what the phrase meant, consuelo, and so, went googling. Look, what I found!!

Plum Nelly:
Plum Nelly from “plumb nearly in the middle of nowhere,” an extremely rural location

This phrase is from a book called the Cotillion, by John.O.Killens. Sounds like a must read; am posting the link below.

http://www.givens.org/curriculum_detail.asp?CurriculumID=113

[aside]I didn't know what a Cotillion was till I read the link and so, for those like me:
From NODE:
COTILLION; noun
1. a dance with elaborate steps and figures, in particular, an 18th-century French dance based on the contredanse.
US: a quadrille.

2 US: a formal ball, especially one at which debutantes are presented.

ORIGIN: early 18th cent, from French cotillon, literally ‘petticoat dance’, diminutive of cotte, from Old French cote.