I didn't go on the facebook, but it actually ran very smoothly. Attendants on the monorail-replacement bus gave out full details and killed off any doubts about checking in, also offered a chace to ask any questions before actually getting to the park entrance. Getting tickets ran smoothly too, with berly any queues to the booths.
It wasn't busy, but as only a small number of rides were open, a few queues were bigger than expected, but they operations were really impressive especially on Oblivion, which only had half the station running, and even with the queue looking fairly look, we only waited 15 minutes.
The biggest annoyance was Air breaking down a lot and taking-off trains/putting them back on, it even ran with 1 train at one point, which seriously slowed things. But all-in-all it was a great day to have for free! I'd be happy if they did it again, maybe with Rita/Thirteen open perhaps. The staff were also surprisingly perky considering the cold weather!