Here is a link to the map that I found that we use each year when we book our Xmas Parade vacation. We have always taken the motorhomes and stayed at Fort Wilderness. It's really great.
As you will see and as the person before me stated, each loop has a comfort station and you never have to walk far to find one. And they are pretty nice, after all, it is Disney World.
One thing I recommend that is fun is to bring a golf cart if you have one. This makes it easier and quicker to go from point a to point b in the park. but like it was said there are buses that pick up at the loops and transport you around.
Have fun!