I just did it about a month ago. As others said it's a lot of walking and a lot of standing - often in the hot sun.
You start at Town Square at the top of Main Street, then walk to the Hub, to Adventureland and ride JC, then go backstage to see the parade staging, then lunch at Pecos Bill, then walk to and ride Haunted Mansion, then walk to the gift shop near Peter Pan and enter the utilidors, and basically walk around the utilidors to roughly midway through Main Street.
So basically in terms of walking you're going to the back of the park and back, but you're doing a lot of standing too.