I'm wondering about this person, though... if they only have about one day a week to spend with their horse, maybe they should reconsider owning a horse at all. They may have to accept the fact that they just don't have time for one. I think riding a friend's horse, or just taking lessons might be a better option for someone with limited time.
Perhaps a friend(s) could do some hand walking or slow riding on days you can not. Maybe this summer you will get more time with your girl.
If we all based our reasons for owning a horse based on time to ride, how many less horse owners and riders would there be? I have two aged horses and if you work them in slowly at the beginning of the season, give them plenty of turnout with other horses to keep'em moving a bit more, they are great... If you plan on doing something more stressful than relaxed trail riding such as hunter jumping, dressage, or eventing, then your choice in horses might be different too. 20 somethings usually aren't usually cleaning up in the show jumping ring, they are TEACHING people how to get there.