i have worked in a few different boarding facilities and can tell you that they are not all created equal. all of them are different.
First off, yopu really need to start calling around. honestly, most good places might already be booked for holidays (i know the kennel i currently work at is at about 75%capacity). most kennels have a lot of regulars, and most of these people book for holidays, so if you want to be able to even board them in a good place, you need to get in it pretty quickly.
I do not like the suggestion of showing up to the facility unannounced. some places will be fine with it and not care, but others can and will not let you in without an appointment. this isnt for any reason other than dog safety. in places that are interactive and have a lot of loose dogs, it is unsafe to have people coming and going, and upsetting the balance the dogs get used to while they are there. the main reason apppointments are set up is so that visiters arent showing up during peak times like feeding, drop off/pick up, things like that. while i understand the motive behind showing up unannounced, i just know how hard it is to make a good impression on a new visiter while the whole kennel is seperated and caged for feeding, or we are right in the middle of checking in dogs, or bathing. if a person shows up, one staff member needs to take time to show them around and answer questions (which can take awhile with some people), which is one less person to be with the dogs. when we know someone is coming to see the place, we have enough staff to cover one person being away, and scedule them during a time when things arent crazy in the kennel.
If the kennel is a cage type situation, where the dogs are in pens most of the day, then make sure you ask how much exercise they get outside of those pens, how often they are cleaned, how often water is changed, how often someone is with the dogs on a daily basis (actual paying attention to you dogs, not just there).
if the kennel is more interactive, ask how they determine which dog goes with who (how do they evaluate new dogs/ how big of a play group they are in/are they supervised/ how long are they out together/etc). you really want to be positive that the staff are knowledgable in dog placement. if you see dogs together, ask why they put them together. again, ask about cleaning, and water chainging.
no matter where you go, make sure they allow you to bring your own food (some places dont for some reason), and ask what they do for dogs that dont eat. ask what they do for vet care if it is needed, and how they go about it. While you are touring, ask about the dogs that are staying there, and see what the answers are. if they are indepth and kind of give more information about the dog than you cared to know, then that person ismore than likely very in tune with the dogs, and knows what they are doing.
I also second not paying too much attention to dogs barking while you are there. the sedong you show up, a strange person, on a property with a lot of dogs, they aill all be barking and going crazy. after you have been there for about 5-10 mintues, this barking should decrease significantly.