And if your dog(s) are anything like my dog, despite the fact that literally every night of her life she curls up into the tightest little ball to sleep, you still need to account for the full-body-sprawl size that somehow permits a 30 lb. dog to take up more space than a 160 lb. human. Small tents can be nice if the only reason you're going in there is to fall asleep, because they are so little hassle. If you're going for one night with the kid and mostly staying outside, a small tent is great. I currently have an ultralight 3 person that's just big enough for two of us, the dog, and maybe one backpack. But it's pretty great to have an extra-roomy tent in places where either bugs or rain can drive you inside. I have a lot of great memories of fleeing from the swarms of black flies, but taking the rain fly off and playing cards while still feeling like you were outside. Especially if you're there for more than one night and can leave the tent up, have space to change or bring gear inside, you don't worry about stepping on your sleeping bag all the time... it can be pretty comfortable.
There's also something magical about getting up early in the morning, crack of dawn type stuff, and making coffee and bacon, and basically tiring yourself out by 1pm... only to crawl back into a nice big tent, in the shade, with a slight breeze going through it... best. naps. ever.
Flying to LA this afternoon for the grandson's 3rd bday and after the week I've had, I can't wait to get out of here and get some airport beers in me