we have a reservation for June with Florida Tours. There are 12 of us and lots of luggage. They arranged a big van to carry all the passengers and will have a small trailer behind to carry all the luggage. I believe it was something like $150 roundtrip to the Dolphin from MCO. Not positve on that, but do remember it was cheaper than 2 vans.
and yes it is a covered enclosed trailer so luggage wont get wet if it happends to be raining.
It isn't on their webwsite but if you call them they will tell you about it.
Bill