Welcome to the dirt bag gang. It is a blast, isn't it. Since I got the Gary Fisher last month my poor road bike has been neglected in the back of the garage. I have found a great trail just a few miles from home. It's 9 miles of up/down rock gardens, baby heads, and narrow twisty parts with lots of roots and mud. It's great! Oh yea, I discovered that when riding dirt it's not so much the miles as the time in saddle. I don't think you can accurately guage the workout based on miles. Get dirty!