Just as a for what it's worth, I have never raced, will never race, find "5 hr century" goals pointless, and have had an absolute ball riding in fast pace lines. If you have four or five riders working together, you get a phenomenal workout that would be hard to get solo, you eat up ground in a hurry, and get to share a unique form of exhilaration. The arguement that there is no reason to ride in one if your only purpose is fitness is wrong, but it gets perpetuated by people who don't want to ride in them.

Long Tom, don't ride in pace lines. But realize that hiking with no head protection is far more dangerous than cycling. I have hiked for years, and have had far more injuries and near death experiences bush whacking than cycling. I was at one point sliding down a cliff, spread eagle, and only stopped because I could snag a root with a lunge of my foot. That snag inverted me, and as I dangled upside down, I realized if it hadn't stopped me, it would have sent me head first into the sudden rocky stop at the bottom.