Thanks for the feedback and advice. I'm trying to work through what will and won't work for me. I KNOW there is a way to make this work, I just need to figure it out.

SouthernBelle - I go to the gym in the wee hours of the morning, while the kids and DH are still sleeping, and/or during my lunch hour from work (kids are at daycare/pre-K while I work). Saturday mornings the kids either stay home with DH or go the child care at the gym, usually the latter so we can all swim together after my class. I can do some weekday morning rides during the same time frame, but need to be home by 7am at the latest, so I'll have, realistically, a 90 minute ride. If I need to to be ready for the century, I'll ride 4days a week in the early mornings plus the long weekend ride, but that probably means giving up some strength training. I could try riding in the early morning and strength training at the gym at lunch time, and then just listen to my body in terms of whether that is pushing it too much to do ride and go to the gym on the same day.

I live in a fairly hilly area, not far from the foothills of the Catskill Mtns in NY, so there are definitely good hill routes. I'll need to seek them out for sure.