Echo, it sounds like you're on the right track. As Beth wrote, there's absolutely no place to spend your money out there except the small gift store in the lodge and the little store across the street. The nearest supermarkets are either in Page, AZ or in Kanab, UT, both at least 90 miles away. There's a Wal-Mart in Page.
As for employment after the Kaibab season, you might think about working for Amazon.com for their holiday season, which runs from September through December, although you don't need to work that entire time. People start when they're available. Express Personnel Services, the agency that handles the workamper program for them, has made arrangements to expand that program to other Amazon fulfillment centers this coming year. So instead of just the Coffeyville, Kansas location, workers will have a choice of working in some of these places as well:
Arizona
Delaware
Indiana
Kentucky
Nevada
Pennsylvania
Texas
Virginia
The pay is excellent, as is the almost sure-thing possibility for overtime. Please let me know if you need more information.
I understand your hesitation about the big step to Kaibab, the "what if it doesn't work out." Your excellent decision to stay on good terms with your present employer will help ease your mind. If I hadn't decided to get off the road for a while and put down some roots in Oklahoma, I'd be coming to Kaibab. I mean, you get to work with Sparkle! As you said, the place will probably never be the same.