I came across the website of The Long Riders' Guild, they describe themselves "Part museum, book store, tack room and Guild Hall, this website contains the world's largest collection of equestrian travel information".
It's a very interesting website which chronicles people from all over the world (past and present) and their journey's on horseback.
There are a few side saddle riders from the past chronicled on there but one stands out the most as she rode only on the off-side!
Her name was Harriet Wadsworth Harper...
"Unlike other women of her time, Harriet was unusual in that her side-saddle placed her legs on the right-hand side of the horse, not the left-hand side. "The family woke up one day to the fact that I had begun to look like a crooked little gnome. Something was wrong, so off I was sent to a surgeon, who ordered a steel and leather brace for me and suggested that a saddle to go on the right side of the horse should be made. This was to help correct my crooked back. No girls rode astride in those days - it was unthinkable.... I never changed back to riding on the near [left] side," Harriet wrote.
But what sets Harriet apart from other Historical Long Riders was not her saddle. It was the fact that she and her cousin, Martha Wadsworth, are the only Long Riders in history to have undertaken an equestrian journey together during which both riders used a side-saddle. In May 1907 they made a 1200-mile journey "down through Virginia to West Virginia, up the Ohio River, across Pennsylvania, and home to Genesee, New York. We stayed at farmhouses, in mining camps, any place that had spare beds."
In an interesting historical aside, one of the "pleasant companions" who joined the intrepid side-saddle Long Riders for a brief period was Gutzon Borglum "the sculptor who carved the heads of Presidents Washington, Jefferson, Lincoln and Roosevelt into Mount Rushmore, South Dakota."