As long as you head straight across, that distance should be no problem on one tank of petrol, even with the stock prop. Assuming you can fill up on the other side before making your way back. Unless you are trying to outrun something.

The first thing that came to my mind? "Vaya Con Dios"...

The 2003 isn't exactly an ocean going vessel, let alone a big river vessel for that matter. I've been on the ocean in a boat about the same length but with three times the freeboard of mine and still had some serious pucker factor going on.