I agree with Indy. While I don't go to the gym anymore, the only time I ever went to spin in the summer was if it was pouring out or there was an air quality alert. I don't haul out my trainer now, either. Instead, I do yoga, core work, or go for a run/walk/hike in the rain.
If you have some fairly uncongested roads, you will be fine. I hate riding on paths for all the reasons Indy stated. In fact, it wasn't until last November that I actually rode on a path near my house. But, it was the middle of the week, in November!
I understand wanting to take the Road Safety course (very worthwhile), but try not to make riding too much of a "project." Like they say in the song, "get on your bike and ride!"