The 1.5K swim would be difficult for most (.93 mile). I raced a guy once across a small lake it couldn't have been more than 1/4 mile and I damn near drowned. I got about half way across and I had to float a few minutes just to recover so I could make it.
Does anyone know off hand how many laps in a Olympic sized pool equals 1.5K?
If you have the upperbody and know how to swim, tri is easier, if not, the marathon is easier because you can walk it( I haven't figured out how to walk on water yet). Of course being underdog, I would just fly it with my girl sweet Polly.