We have KC here, had it a few days but I didn't twig until yesterday as Rai is the only one who's coughed until yesterday, and only very very mildly.

Today one of her neck glands is huge - small orange sized.  I'm assuming this is the KC and it has just come up today - is that a safe assumption?  I don't want to take her to the vet unless it's absolutely necessary - the stress of being looked at will trigger enteritis through stress and at the moment, her appetite is brilliant (too good lol!), she's in good condition and happy and playful; she'll get over the KC quicker if she stays that way.

I don't routinely take mine to the vets with K.C. though, before I get shouted at, I would if they were ill with it. K.C. is a virus, not a bacteria so antibiotics are a waste of money and an unnecessary thing to give the dog. My vet of the past said to me once, "It will clear up in a week with antibiotics or 7 days without."  A rare honest vet I feel. The lymph nodes will enlarge but don't panic unless she is unwell.  It should subside in a few days but if you are worried, go to the vet.

I am the same - we had it year almost 2 years ago now, and only one got taken in then as she was already stressed (fosfter with a bad start who'd only just got here) and was not well at all with it bless her.  As you say it is a virus so not much to be done though usually, I'm certainly not going to risk enteritis with Rai unless it's essential she be seen. 

That last bout was a lot worse too - it's the gland that's spooked me, it's not something I've ever seen on a dog (Rai wasn't here through the last bout so no idea if it's usual for her, don't think she's had KC before though).

>K.C. is a virus, not a bacteria

Bordetella bronchiseptica is a bacterial infection, not a virus, which is why the vaccine only gives short-lived immunity. Kennel cough information.