Well this is a somewhat generic response, but I've found packing has more pull than the carry on size itself. So my suggestions is 2 gallon zip lock bags. You can get two-three pairs of pants into one, squeze out the air, and it takes less than half the space. It's basically the same effect as those expensive storage bags, but disposible. Once your basics are in those bags, you'll have enough room to lay your suit on top to prevent wrinkles.