Shes lucky to have a friend like you
I had an off-the-wall, silly, unserious idea as I read your post about her not wanting to give up biking... but if she has a sense of humour you should suggest/ play-threaten her with something like this if she has a down day...

Line up your cookies round the house and make her walk to get em --- kindve a chocolate MS treasure hunt...

Enjoy being with your friend tomorrow... I'm sre she'll love seeing you