So I've got my new bike and I'm riding between 20-35 miles each time out given my time constraints. In ten days there is a local event that has three distances...30, 55, and 70 mile rides. Obviously I can do the 30 mile ride. I'm just wondering whether to do the 55 or 70. I'm leaning toward the 55 just to be safe. But do you think I'd be in over my head doing the 70? Should I wait till I'm doing 50's frequently? I'm working toward a century ride this summer. When I finish my rides these days, I am not tanked and feel like I can go lots more. Thoughts?