Originally Posted by Mr. Wooden Alligator
He could visit Sothoryos in one of the last two books, couldn't he? I'm certain in a video interview Martin had an interest in much smaller scale stories set in his world. There's also a TCG out based on ASOIAF, so perhaps he has become more lenient toward fanfiction or, at the least, a semi-shared world approach.
But I ask again what does fanfiction have to do with anything? Him writing other stories and releasing info on other parts of the world isn't fan-fiction.
And, yeah, it is entirely possible he could explore Sothoryos in the next two books, tho, he has said they go further North, but I guess some characters could be heading South for some purpose. With GRR Martin it is hard telling what will happen. The man doesn't believe in straight lines. His stories divert and meander every which way before they conclude.