In Portland, there are not only women's rides, there are shops that cater specifically to women. Bicyling magazine has been publishing articles on them lately. If she wants something like that, look into those. However, is this what she wants or is this what you want?

I remember 20 miles as being a point that took a few rides to get past. That and 80 miles. I have a buddy who took forever to get past 60. It is just a matter of conditioning and getting out there to ride.