Originally Posted by dwanthny
I've been using the Kindle Previewer to do just that. Adding an entry into the "Open With" plugin has been very useful, though the file still has to be opened manually after Previewer starts up. Even with the extra step, it's better than loading the book onto the device and finding out the hard way.
One other thing that's been useful in seeing whether the nav points are coming out right or not is to watch the conversion job while it's happening.