I would figure an hour or so. May be less, may be more, but unless you watch from down by the train station it will take a while to get to the bus stop, very possibly 10-20 minutes while waiting for buses, and then another 15 minutes to get to the resort.
You may luck out and get right on a bus, or you may end up having to wait much longer, but we usually end up getting back 45mins-1 hour after the big events let out.