in addition to all of the good advice you have had so far, and regardless of whichever ride you decide to do, bear in mind that once you have the right shorts, the right fit a way to carry adequate hydration and nutrition, it's all about TITS time. Build up the time that you can spend in the saddle between breaks. This should also, obviously, lengthen the distance between stops. Depending on the speed you can achieve, this can mean the ability to ride 20-30 miles at a shot between stops. Sometimes the saddle time is almost as important as speed.