Oh, I'm sure that you'll feel much better in no time Remy and you'll be able to go out more often :)
Yes, you can walk there anytime. But the shop/farmhouse is only open during certain times (from 10AM until 5PM - I think)
You can still bring her there this year. The track is open until 5th of May so you have a lot of time - if the weather permits you to go there :) I'm sure she would love it. It's impressive.
Oh yes, we have a little niece and spent a lot of time with her. It was a lot of fun! We also went to Heusden with the family and had a dinner together at my brother's in law place. It was a lovely long weekend!
I'll let you know when I'll be going there next time ;)