I may be wrong, but I thought the website had a list of hotels that they recommend. I would imagine that these would all have shuttles. The success of the Festival depends on us spending money. And they work hard to make sure we get there and enjoy a good show with a lot of vendors.
As to my friend and I, she lives north of Houston, so we drive in every day. There is parking available, but all of it may not be close. Close to me is within a block or two. The Toyota Center has a really large parking garage. There are some open flat parking lots near the Festival.
http://www.quilts.com/home/shows/index.php