What to do during long vacation

We are planning an open ended driving vacation that will probably be 2-3 weeks long. My daughter's corn snake Indigo is a little over a year old, 23 inches long and in a good sized tank (20 gallons). We have 2 water bowls, both good sized.

We will have a cat sitter coming in every 2 days, but I'm not sure if she will be willing to feed Indigo or clean his tank, though watering shouldn't be a problem. If she won't feed and clean, what's my best option?

Is leaving him for 3 weeks without feeding or cleaning reasonable?

Or are there places we can "kennel' him where he'll get good care while we are gone? We are in Phoenix, Arizona.

It would be really nice if you could arrange one feeding right in the middle of that. The problem with having someone else feed is you have to leave his heat plugged in (I always like to unplug all reptile heat before leaving for more than a couple days), the risk of escape if his viv isn't closed correctly, and pooping in his water bowl. I'd be very comfortable leaving a yearling for two weeks. Three is stretching it a little, but it's probably okay.

You can leave him two water bowls, or have the cat sitter pour water through the screen lid without opening the viv (much safer than having anyone open it).

How often are you feeding him now?