I ride just about every day, weather permitting. It's great excercise. Try to find a trail system nearby where you can stay away from cars and the flatter the better. I don't like going real fast cause you just never know. I think I average about 10 mph on the level and hit the brakes somewhere between 15 and 20 mph on a downhill. And, yes, wear a helmet. Some places it's illegal not to. Green Lake would be okay except you'd need to go really early in the morning to miss the crowds. I used run around that lake 15 years ago and I remember thinking it was too croweded for bikes then.