In addition to the previous poster's suggestion of watching outside the train station, when you leave... do a quick visual and evaluate your three choices.
The resort boat will stop at GF first, but is a nice ride and relatively quick. Avoid it if there is no boat at the dock (or approaching) or it looks like the line is already long. Each boat probably seats 25-30 depending.
The ferry drops you off within 5-10 minute walking distance of Ohana. I'd take that if one is loading when you look and the rest of the line looks like it will fit, or if there is another one ready to load.
Third choice - monorails. All depends on the lines... if the resort monorail is short, take that. Or, if the express monorail is short, take it and walk from the TTC (same walk as the ferry). Given the recent postings about monorail problems, I would make this my last resort if time were of the essence.
Any of these means should take less than an hour, (maybe <45 minutes) especially if you get the leg up on the thousands of others leaving at that same time by viewing from the very front of the park and then make haste leaving. But, I'd plan on the hour just to be safe. You could always sip on a Lapu Lapu if you have time to kill at the Poly.
