I'm new to riding -- have been riding a beat up old bike about 60 miles per week for several weeks and before that would ride mostly at the gym for about 45-60 minutes at a time for over a year. I've never ridden a charity ride, but want to do Ride for the Roses in Austin in October. I need to sign up for a distance -- any suggestions between the 40 and 70 mile lengths? I'm leaning towards 40, which I really feel I could do, especially since I'm training more and more each week. Any advice? Thanks!