For ease, safety and awesomeness of travel, I'd choose a redstone Flying Machine.
Edit: and here is a design I made a few days ago.
The machine :
It is symmetric, and its direction is determined by the position of the outer redstone blocks. On this picture it will go to the left.
The dock :
Pay attention to its orientation. The sticky piston on the bottom left should be on the side of the machine where the slime blocks protrude (i.e upwards in the picture of the machine). The obsidian block (or any non-pushable block) should line up with the pistons of the machine.
Note that the seemingly useless redstone line at the top of the picture is crucial. It provides the block update that kickstarts the engine.
Detailed view of the dock :
It doesn't need to be that fancy. Its task is to swap the positions of the outer redstone blocks when the machine arrives. Build two of these aligned right, and the machine will be able to go one way or the other with a single button click. You heard me right, fully automatic !
Put a minecart chest on one of the boats (place a block above, a rail on the block, a minecart on the rail and break the block). It will follow along !
All pistons with lime wool directly above or below are sticky, all the others are normal.
This contraption works as of 14w34b, and worked on several versions before (I don't know when the fall-through bug was fixed). It does not work on 14w30c, though.
I apologize for the jpg pictures. No idea why Pinta output that.