In my younger years I used to camp with an Irish Wolfhound, collie mix, and basenji mix - in a small dome tent! They were good about staying in the tent when we were there with them.
More recently we tented a few times with a standard poodle and a Rhodesian ridgeback. It was fine, except for the dirt tracked in by their paws - they refused to take their shoes off at the door ;-)
I'd have no trouble tenting again (aside from getting up off the ground myself, oh yeah, and no bathroom in the middle of the night). I do sometimes put up a tiny tent when we are rving just so I get the feel. One or more dogs always come with me.
I suppose if they were prone to poking their noses/selves out the door you could use a big clamp to keep it closed at night.
Sounds like a fantastic trip!