Hello. I am a lurker here and new to the forum.

I agree with the previous poster that horseback riding is a fantastic option.

I am surprised there are not any indoor pools near you where she could swim or the two of you could do water aerobics together.

Yoga is a surprisingly good workout and some kids enjoy the opportunity to get lost in their thoughts in a soothing environment.

Skating can also be a nice nonsporty activity.

Another option is that you could do a weekly active adventure throughout the winter... eg week 1 yoga, week 2 skating, week 3 find a trail for hiking... etc.