You could look up how to make a custom imm brush, using 3 different objects so you create one ruffle, split it and make a continuous pattern of ruffle along any of the paths of your choosing, using the stroke lazy brush option can carefully lay down that pattern. (which you would probably do at the very end of the lower body, when its pretty much at the final stage, so the last thing to do.)
Cause messing with it before adding it last would probably cause more issues if you decide to change it later on.( something bothering you about the way the dress lays) as an example. (forcing you to redo the ruffles entirely.)
Hope that helps, the idea i had for the ruffle would be think of 2 S shapes slanted side by side, so two up hills merging to the center (top of the hill).
Then you can carve out ripped strands if that is how you want to do this, i think keeping her somewhat clean and going light on the damaged ruffles would be best for a beauty piece. (which is how i see this.)
