What is your budget?
You really need to test ride your bike. Especially since you are new to road biking and want to do a long ride.
The difference between mens and womens should be fit. In general, they figure women have longer legs in proportion to their overall height. Not true. Some are evenly proportioned. Some women have shorter legs. Some men have longer.
Suggestion. Start test-riding Jamis bikes. Both mens and womans. You don't have to buy it if you don't like the color.

You get a lot for the money with Jamis.