You are away for a week and your dog is 13 months old. You have spent 3 months on recall and settle, and you are picturing all of it coming apart in a kennel.
The honest answer is that you will probably get a rough 1 to 2 weeks when they come home. That is not the same as losing the work.
Why the dip happens, and why it is not lost progress
For a week nobody paid the cues you have been paying. Your dog practised whatever their new environment paid instead, which was probably barking, arousal and other dogs.
Add adolescence to that. Reduced responsiveness to the cues of the person who raised them appears around the onset of the stage, and returns later in it. Your dog was already a bit patchy.
Add tiredness. A week of broken sleep in a noisy building produces a dog who cannot hold a settle. That is sleep debt rather than character.
Nothing your dog learned has been erased. Behaviour that has been rehearsed can be rehearsed again, and the comeback is a smaller job than the original.
What to ask a boarding facility
Ask these on the phone or in person, and listen to how readily they answer. A facility that has thought about it will answer plainly.
What do you do when a dog will not do what you have asked? This is the question to ask. Walk away from any answer involving a prong collar, an e-collar, a spray, a scruff, or pinning a dog down. The same goes for any talk of being firm to show a dog who is in charge.
How much of the day is a dog alone, and how much is with other dogs? Group play all day with a mixed group of adolescents is not rest.
Where does my dog sleep, how quiet is it, and how many hours of undisturbed sleep will they get?
Can I see the actual room my dog will be in, today, rather than photographs?
How many walks, how long, and on what equipment? Bring your own harness and ask that it is used.
What is your vaccination, insurance and emergency policy, and which veterinary practice do you use?
Who is on site overnight, and what happens if my dog stops eating or will not settle? Ask how they would contact you.
Reward-based methods are what is recommended for training and behaviour change, and aversive methods carry welfare and behavioural risk. That standard applies to the week you are not there.
Dogs trained with aversive methods have been found to show more stress-related behaviour than dogs trained with rewards. You are not obliged to hand your dog to anyone who works that way.
Practise before the real stay
Book 1 day, then 1 night, then 2 nights, in the weeks beforehand. A dog whose first stay is 7 nights has been asked for a lot.
Visit twice before that: once to look around, once to walk in, be fed, and leave again.
Practise at home what the stay will need: handling by a stranger, eating in a new place, and settling with noise around.
Keep the last 2 days before you go ordinary. A frantic weekend of extra activity does not bank anything.
What to send with your dog
Their own food, measured into labelled bags per meal, so nothing changes about their gut in a week you are not there.
An unwashed bed or blanket, and a worn t-shirt of yours. Smell is the cheapest comfort available.
Their own harness and a plain 6 foot lead, plus a tag with your contact details, and check the microchip details are current.
Any medication in its box, with written instructions and the dose, not spoken instructions.
One page of notes: what your dog can and cannot do, the words you use, what frightens them, and your veterinary practice.
2 or 3 chews and a stuffable toy they already know, so at least 1 familiar activity travels with them.
The first week home
Do not pick your Plan up where you left off. Restart it, at the beginning, on easy criteria, in the easiest place you have.
Give 2 or 3 quiet days first. Short sniffing walks, no dog parks, no visitors, and a lot of sleep.
Pick 1 skill and 1 only for the first fortnight, and put food back in your pocket for it.
Halve the criteria. Recall from 6 feet in the hallway before recall at the park, and 30 seconds of settle before 10 minutes.
Put the long line back on anywhere your dog has run off before, for 2 weeks, whatever they were doing before you left.
Expect the house rules to need repeating: the counters, the bin, the sofa. Manage them rather than test them.
Behaviour change is built from management plus reinforcement, so put both halves back at once.
Relaxation is trained as a behaviour in its own right, in short repeatable sets below your dog's threshold. That is the most useful thing to rebuild in the first week home.
Safety note
Get help now if your dog comes home not eating, coughing, limping, losing weight, or frightened of things that never bothered them. Book a veterinary examination, because sudden behaviour change warrants one and pain frequently presents as a change in behaviour rather than as obvious lameness. New growling, snapping or fear after a stay also needs a qualified behaviour professional rather than a training plan.
Today's version, in one line: ring the facility and ask what they do when a dog will not comply, then book a single practice night.