Interesting you mention Fire & Ice, I read the first three primarily on Kindle for iPhone.

I did get into the habit of bookmarking my current page to reference the maps and appendix. Generally my biggest problem with "sync to furthest page read" was reading while underground (subway). Usually I just fire up the iPhone briefly so it will sync forward if I want to read on a different device.

There is also the "Book Extras" section which, for Ice & Fire, includes content from Shelfari with some appendix info and does not break the furthest page read. It would be nice if the official appendix and maps were included in a similar format.