Mine are out two weeks after the first vac.
Yes I would take the dog with me provided the other dog will be a good influence and you know the people well. You can't board a dog until it has had all it's vac's C5 + 2 weeks.
But I repeat I do this at my own risk.
The vet will never say to do it. They are looking at it from a health perspective, whereas I'm looking at it from of socialisation point of view.
It's one of those things where I am prepared to take the risk, but understand if other do not and again it is a risk.