This is an expanded version of hpapillon's Exotic Castle tileset. It's a non-overriding reskin of the Castle Interior tileset, with added windows (two varieties), rounded corners, blank tiles, dais, usable beds and stone room baths.
Actually, I just recalled that in gaoneng's original window hak there are placeable "skyboxes" that you can use to get different views. One of them is a desert, so there's no need to modify the hak. :)