Your plan makes sense. Build up a tolerance for bike commuting, and in time, you'll build up a tolerance for doing it in bad weather. You'll find what your limits are with how much rain and how low a temperature are tolerable. My own limit is about 25ºF. Because of the street layout and the nature of traffic and the way snow melts and refreezes in this area, I prefer not to ride when there is snow or ice on the ground.

I sometimes arrive at work wearing bike shorts or tights. It is a little embarrassing, but I try to look as if it's not. No one says boo, so I figure I'm OK. I've found that corduroy pants, the kind styled like jeans, are nice for riding when it's not too hot. They're also decent when I roll them up to make them look like knickers. Levi's makes something called commuter jeans, which I haven't tried. There are also loose fitting cycling clothes, usually aimed at mountain bike riders or just more modest people. Generally, I wear cycling clothing when it's hot and street clothing when it's cold, but I don't live by hard and fast rules on that.