Why would you risk it for a few dollars of antifreeze and a few minutes of your time. If temps drop dramatically while you are away, and that can happen in Kansas, lets be real here, your time and expense involved to repair any damaged plumbing will have you kicking yourself. Just winterize it, and have peace of mind. If you really don't want to do that, then check what your forecast is while you will be away and if it doesn't appear it will get real cold, you could always simply blow out your lines with compressed air. If you don't anticipate using the trailer for a while after you get back, then that puts you into December, then you should just winterize it properly. You probably already know this....but sounds like you should have already done that!