I spoke with Ed several years back at PentaCon in Fort Wayne. This is one thing that I asked him straight up. Two items stuck in my memory.
First of all, the Moonshae Islands are very different in his own campaign. They are more like Earthsea, with lots and lots of little islands, and there is no Celtic/Norse pseudo-Arthurian story going on there. Lots of different little cultures, though he didn't go into any detail.
Second, the Great Glacier is much further south; in fact, it is a mirror of Anauroch. Thus, for example, the Glacier of the White Worm is not a remnant, but actually part of where the Great Glacier is. Apparently TSR thought the glacier went too far south, so they redesigned the layout. The Ride used to be much bigger, too.
Oh, and IIRC, the "Real World Cultures" of the Realms weren't really there in his campaign, those were later additions.
That's all I recall, really...