With sincere respect: I do not think it is 'far fetched' to be considering any deviation from what is considered normal in the life of a woman on the day she vanishes into thin air
The kennel stay had to be planned in advance, it is not something of the day she vanished.
A young dog can make a mess in a trailer, he probably wasn't trained enough for them to trust him not to do damage to the new purchased object while they went hiking. IMO