I can not call myself a runner, just a wannabe. But I will say that trails are much easier on me than roads, sidewalks, or asphalt tracks. As long as you keep your eyes open for ruts, roots, rocks and such, I think you may really enjoy it. My trail runs beside a river, so it is always cooler and breezier with lots of trees, plus I get little hills that are fun. I think there is a cushioning factor on the trail as well, because I never get shin splints and the only soreness I get is from digging hard up the hills or pushing to beat my time.
Julie
ETA: Oops, sorry...you were asking about race times.....