Yes, you can take the boat from MK to the Trails End at FW...it is a very short walk from the dock.
As for your second question, I'm pretty sure that you can also do the buffet by "take out"...meaning they give you a container and you pay one price and fill it. Not completely certain on this, but I thought I remembered seeing something like this when we stayed at FW. You can also do the buffet (all you can eat) and eat there.
Marcy