Thank you! I ended up going with them. I can't recall the name either, but I was directed there after a long (and very friendly) string of taxi companies pointing me in the right direction.
So people know, it was a $50 deposit, and we'll have to pay between $80 and $100 in cash to cover the balance ($130-150 total). Pretty steep, for sure, but we're on a tight timeline, the cost is split three ways, it provides my partners with some peace of mind, and it ends up being cheaper and environmentally preferable than a second car on the ferry - and a bit easier than hitching a ride. And hey - $50 a head to get our tired and muddy selves back to the car and put some cash directly into a local small business owner's hands? There are worse places to spend money.