My goal is to do a fairly flat terrain metric this year. I've been spinning three to four times a week at an hour each time. The classes are grueling (for me anyway). I've also been eating better. I'm wondering if the classes are enough training or do you think I should get out on the road on the weekends. If so, how many miles on Sat and Sun should I ride? The most I've ridden at one time is 42 miles. By the way, I've lost 5 lbs since Jan 1 because of my regimen of spin and cutting out Big Macs.