There is good advice here. I am another who will not ride without bike shorts. Period. Not for any distance, why ask for trouble? It is great there are women who have found they can ride without them for some distances, but for me I will not.

Bike short choice (and saddles) is very personal, and there are a lot of options. Our butts like what they like, and what works for one woman may not work for another. Not all bike shorts are tight fitting lycra, and you can also purchase liners that you can wear under other shorts. Terry and Pearl Izumi make these, and I am sure that others do as well. I've a pair of Terry liners that came with my mountain bike shorts and when I need a separate liner I turn to them.