If you're worried about having too many long skirts you could take them to the cleaner's if you have a good one that does alterations too? I do. Then you could have long, medium, and shorter skirts and could figure out as you went along which would be a good choice for whatever you were doing.

I would wear a long skirt as the bottom of a coverup for my bathing suit. . . if I still had a bathing suit! :-)