I don't think I would risk it. We have a 3:00 flight in Oct, and we're staying at BW..I booked our last meal for Cape May-Goofy's Beach Blast Breakfast, for 9:00. We can just walk there in 6 mins., eat, and then head back to BW. We'll have to be at the bus at noon, so we wouldn't have time to make it too much further away than that.
You should not count on it taking you only 15 minutes. If you eat at 11:00, take about 45 mins to eat...that's almost noon when you would be done. Then, it's going to take you 10 minutes to get out of the park, then a possible 10 minute wait for the bus, then another 15 minute ride back to POP, then collect your bags (another 10 mins)....nope, I would feel way too rushed to do this. Of course, you could always catch the next bus, but if it were me...this would be the time that everything took twice as long as it should. I wouldn't get back to the bus at POP until 1:00, miss the correct bus, so have to take the 1:20 bus,traffic would be tied up due to an accident making the normally 30 min. ride more like an hour, then I would get stuck in a 90 minute security line, then have to make a mad dash for the gate to find they were going to board in 10 minutes!!! Okay, so probably not going to happen that way, but I would so much rather be at the airport, bored out of my mind than worrying about not getting there.