I saw a few tutorials on YouTube utilizing the cloth sewing spring method and I'm trying do such a thing with pants.
If I were you , I'd model pants from a box(mirror, extrude, some subdivs) or shift-d and separate legs. Next I would sew them to shirt or something and add sew along pants to add folds. I'll attach .blend here. There're some issues with subdv but its only example which took 5 min. Hope I'll help.