The attitude of the pair who actually drove us to the park saved this review from totally trashing Mountain Shuttle, but here is how it went.
We'd intended to stay at Mountain Shuttle Freedom Camp the night prior, but couldn't find it because there was no signage. Our contact from the website basically told me to "look at the map."
Had I been given some adequate information I'd have rated the experience an 8, because the shuttle was only about 15 minutes late (waiting for a late passenger) leaving for Tongariro, and the driver and the other staff person were pleasant, so I don't fault them.
Shame on Mountain Shuttle for not giving adequate information, and causing undue stress to their customers.