Jennie,
Yep, that is when I would add it. Just cut your batting a little bit smaller than the sewed runner, so it doesn't bunch up too much. I think this would be ideal for simple machine quilting of straight lines. I think I already said that once. LOL Just look on the batting package to see how close it says to quilt. Some of them can be quilted 10 inches apart. This wouldn't have to have batting and would be lovely just like it is, but adding the batting would just make it a bit more special, in my opinion. LOL But since I am a quilter, I am a bit biased. LOL This would be a project that could be done in a couple of hours. I know it is supposed to take a lot less time than that, but I don't like to get in a hurry. LOL When I rush, I make mistakes. I haven't decided what to do for my daughters yet, but may try this. If I do, I'll try to take pictures as I go and post. No promises, though. LOL
Blessings,
Winona