I’ve never used DN on CPRS but I like Sue’s idea of needling the proximal LE, lumbar, opposite LE. Anything to get her to focus her sensation on something else. You may want to consider her low back pain as being secondary to L ankle pain or antalgic gait compensation and treat her LBP that way.
I also think that the fact that she is open to trying DN is a huge advantage for you. I’d like to hear what the result of her treatment is.
-Mark