That property is approximately 200 acres, and yes you can walk it as I did the first 5 years or so I attended. If you want to spend all your time walking, that's fine, but I usually attended 2-3 days previously, and this year as well as last year I probably will only attend 1 day, so if you have limited time, you don't want to be on foot, lots of people ride bicycles too.
This has been my wife and my mode of transportation at Norwalk for the last 12 years, or so:
At this late date the carts may already be sold out, they usually are. They will let you bring your own cart through the gate if you already own one, but you're probably not going to have room to bring one from Texas, and return with it after picking up your purchases.....