Yeah, I don't think road riding will anger my back. I won't go out on my mountain bike on days when it's bothering me...plus I really don't like doing that alone. I am too fall-prone and don't like the thought of crashing and being unable to get help.
In the Winter I have far less issue getting out for runs. It has to be really nasty out before I will second-think a run. Even if it's <0 I will usually try to do at least 2-3 miles for some hardcore points.
Now the sun is trying to come out, but it's sorta teasing...temps are up to 44, though. Hrmmm...?