I don't think that one or two W's will be a problem, especially if you are doing well in your other classes. They understand that when you start doing your prereqs things might come up that will make you need to drop a class. If you end up with a lot more W's, though, you might need to explain it.
I was really considering getting a R in a class as well which is the same as in withdrawing, however im applying to an accelerated program do you guys think that it will look bad in making it seem like i cant handle the work load?