If by 'bathing suits', you mean the kind that look like shorts, but are made out of thin nylon - so they dry fast - we are already on that suggestion. We learned that from our Six Flags visits, but it applies here even when the weather is sunny, as there is plenty of opportunity to get wet in all of the parks, with or without rain. The options for girls and women are a bit less simple, as Disney probably doesn't allow bikini or one piece women's suits to be worn around the park (any more than Six Flags does in our area). But, my wife and daughter have thin nylon pants that the can wear too. We brought dry underwear, sirts, and socks yesterday, to change into when we tired of being wet.
Yes, I also prefer the rain to the crowds. I kept telling the kids that they didn't know how lucky they were to just be able to walk right on to all the rides at Magic Kingdom on Monday. We could have just stayed on the boat at the Pirates of the Caribbean ride - we were the only ones on our boat, and no one was in line to take our boat when we arrived at the end. We rode Big Thunder Mountain enough times in a row that I was starting to get a bit sea sick. We could have done the same with Splash Mountain, if I was willing to get wetter (front row seats on our first trip dampened my spirits for that ride
. The worst though, was the Indy Speedway. The skies had cleared when we got in line, but opened up with a torrential downpour, as soon as we loaded. We were riding in a bathtub, by the time we got to the end. No one was waiting in line to get in the cars when we did get to the end (of course), so CMs were moving the cars forward to make room for the arriving cars - which took forever
. We had to go home and change after that experience, but came back later for even more wait-free rides.