I am a VERY new rider, 55 years old, have not ridden since childhood. My husband and I have both taken it up; he has ridden more recently than I. We have been "in training" and have done some longer rides lately. (20 miles is "long" for us at this stage in our development!) I can go the distance, but my seat is uncomfortable and I get chafed and irritated. What is a good seat? Also, do you wear undergarments with biking shorts? Tampons? Pads? What's best? I'm old - but not yet beyond that stage! I need tips on how to stay comfortable. Thanks!