Thank you for all the nice comments above. I hope I didn't dwell on the few negative things too much, as it was one of the best vacations of my life.
Also, thanks to all the Dis Board members who provided fantastic tips and responses to my questions before the trip.
Palo was excellent for GF. The one thing the server did that was helpful was to get the chef. The chef came out and walked around with my wife to go over her options. There were many GF options on the buffet. He then said he could prepare just about anything for her that she wanted. She ordered GF pizza, which my wife said was very good. She raved to the chef about it and he brought out the UPC from the box for the crust they used. We were a bit disappointed to see that it was Amy's pizza crust, because we know that Amy's is not made in a GF free factory. Disney claims to be very aware of cross-contamination, so I am surprised they wouldn't know better about purchasing from GF factories too. But, my wife didn't have any reaction to the pizza. She didn't order anything else, and the waiter didn't offer to bring her any GF deserts. I don't recall if there were any already available, but she didn't get any.
My wife really liked the GF cookies from room service. One night, I ordered 3 of them (she saved 2 for the next day).