Your ME bus will pick you up at your resort around 2:40. If you leave anything with your hotel's luggage services (like your carry ons or jackets) you will have to get those. Also, keep in mind that the bus from the park to your resort may not come right away. On one trip, if our ME bus wouldn't have been so late we would have missed it. We had to wait over 45 minutes for our POR bus from AK one afternoon, and then it stopped at PFQ first. By the time we made it to POR it was about 10 minutes after our ME bus was scheduled. We lucked out because the ME bus was late.
So, now we always make sure we leave in plenty of time. If I were you I would plan on heading out of the park at 1pm.