The weathersealing on the body does make it a whole lot easier to protect the camera, at least. When I was coming up there was no such thing as a weathersealed lens, for any purposes of mine, anyway. The one thing I found about the kit lens in snow is that it's plastic, and especially since it wasn't terribly cold, (We don't get a huge lot of snow down here) the surface of the lens body didn't get chilled and the snow therefore kept melting immediately, and that was enough to make one nervous. There's always the old poke lens-through plastic bag and rubber band it to lens hood technique, of course. You just have to show some due caution. Often just flipping the end of your scarf over the camera and lens will do it. (I've got a pretty big scarf that actually started life as a sarong or something, that I can actually just pull up over my head, camera, and all, which is fairly handy with snow, and also cause my eyes don't get along with very bright snowy days. (Which was a real issue back up north when I was using my little compact camera with electronic viewfinder a lot more. If I ever dashed outside to photograph something, I'd often just pull my wrap up over my head like an old focusing hood.
)
I'm curious about the coming 18-135 WR: that looks like a great one to have weather-sealed, if the image quality's good, and with that range, you might not have to worry about changing lenses at all.
As for the bag, I peeked. I'm not sure if you're wanting to avoid 'looking like a woman' or the opposite, but I think the way that's supposed to be carried, you're OK, either way.