Great thread, Ben. That's the biggest question facing the traveling turkey hunter: How can you know for sure that you've chosen a trustworthy outfitter?
I recommend obtaining references from folks who've hunted with an outfitter. Moreover, I want to talk with folks who hunted with that guide and did not take an animal. If they still recommend the outfitter, I feel much better.
Further, ask the outfitter about everything, including meals, lodging, schedule, realistic expectations, etc. Leave no stone unturned.
There are, of course, numerous other steps you should take. Let's hear some suggestions!