I hate leaving my dogs in the kennel too! Here are some things I look for...
-- Use a vet's kennel. My biggest fear is that my pets get extremely ill and the staff won't even recognize it. Actually, my usual kennel (a vet friend's kennel, we don't have a kennel where I work) was booked last week, and I had to send my kids to a non-vet kennel. I had to give them a lesson on "bloat," a common fatal condition that big dogs get while kenneled. They didn't even know how to prevent it or that it was a deadly emergency!! Oh, and when I picked them up after 3 days, one was very depressed and not eating or drinking. They didn't even notice.
-- Use someone who has someone there watching them 24 hrs. If your dog bloats during the night, it could die. Other things that I fear are choking on toys, getting toes/noses caught in grates or gates, kennels catching on fire, etc. Can you tell I'm paranoid? (btw, I've only ever found one kennel with 24-hr care)
-- If the kennel is not with a vet, or is a day-only vet, make sure they have a policy that they will bring the pet to an emergency center if needed and will foot the bill until you can be reached. Some places won't transport a dog for fear of getting chewed out by the owner when they have a $2,000 bill for emergency care, and then get stuck with the bill. Oh, and be sure you sign the paper saying you will cover the bill. I stress this every time I drop off, that I will pay for ANY emergency treatment needed; I try to leave my credit card # if I think that's what it will take.
-- They should require vaccines and flea/tick preventative. Minimum for dogs: DA2PPC annually, rabies 1-3 yrs, bordetella every 6 months. Your dog won't be protected if he gets the vaccines when you drop him off, if he isn't already up-to-date. There's no good way for a kennel to get around this, but it's good for you to know.
-- Get the tour. Some kennels don't even have fenced yards; they just leash-walk the dogs. I wouldn't trust some kid leash-walking my dogs, and I want them to be able to run around a bit when they're kenneled most of the day. I also look around for cleanliness (obviously), proper temp, organization (labels on cages of when fed, etc), and fences... how difficult is it for my dogs to escape, etc. A low chain-link fence by a busy road is a no-go.
-- Bring your own food to help prevent stress colitis, as well as toys, beds, etc. as long as your dog isn't a chewer. My dogs are allowed toys during the day, but I have the staff remove them at night, just to make sure they don't swallow anything while no one is there.
-- Some pet resorts give you video access to your pet 24-7 over the internet. I would definitely go for that if I could find it and afford it. Then again, it would probably cost about the same to have someone house-sit while your'e gone, if you can find someone you trust. That's the way to go, if you ask me, but I haven't been lucky enough to set something like that up.
-- Type up a little paper for your kids... what to feed, when to feed, what toys you brought, any rules you have (2 dogs must kennel together, do not feed together, harness only/no collar), their dispositions (has separation anxiety, may bite if you try to brush, limps after exercise, gets hot spots when kenneled/please treat), and medications. Some kennels will think you're silly and ignore these, but I've found them to be a great help when we're unsure if a pet is acting sickly or if the condition is normal for the pet.
These are just some things off the top of my head. Yes, I am one of those crazy pet owners!