You can absolutely wander to and from and Disney resort at you please. The only thing you should not do is swim in a pool that is other than the resort pool you are staying at. Otherwise you can browse, shop, eat, exercise or lounge to your heart s content. We have never once been questioned as we tour other hotels, and we spend a full day doing that every single trip we take to Disney.To answer your question, yes you can absolutely walk to the beach to view the fireworks without any issues. You may also be able to see them from other spots around the water. And, you can always go hang out outside of the MK for fireworks. We were in line to catch the ferry back to the campground and had a perfect view of Wishes.EDIT: I just want to reiterate that we have never ever ever once been stopped by a guard at any of the Disney resorts. No-one ever questioned us as we entered the resort, browsed the gift shops, ate a meal or wandered around the outdoor pool/beach/play areas.
There is a guard at the gate of the Grand Floridan, just like all the other resorts. They will stop you when you arrive, but just tell them you re going in to shop the Gingerbread House and watch the fireworks. Enjoy the resort grounds, and head over in the direction of Narcoosee s Restaurant. There are some benches on the pier you can sit and see a great fireworks show. The restaurant also has the music piped in, so you can really enjoy everything there! We always spend our last day there to watch fireworks! You can also check out the new Bay Lake Tower from there - it s a beautiful view! Enjoy - the Gingerbread house is incredible!