Awesome info everyone! There's a reason these forums are my go-to. Looking at a lot of the parks in Yellowstone, it seems most of them do not offer hookups. Glad to hear there's one. We're looking to go after labor day, so I'm hoping this is far enough in advance to get a spot.
Also we are considering Tetons instead, and maybe a day trip or 2 to Yellowstone. Either way we're definitely going to both. Hookups unfortunately are a must, as we'll likely need the ac for the times we need to leave the pups behind. But I'm also reading about various doggie day care services, so maybe we can go dry.