I set a goal of 250 miles/month. I regularly do 100-150 more than that but for me that's a pretty good balance.
I'm trying to balance being a newlywed, my first season of racing (leaving enough energy for the actual race), work, and the rest of my life so I'm doing closer to 250 side.

I usually put in about 5-6 hours a week. I'd like to do more than that but that will take riding before and after work a few days a week.