PlayOn via Avia works
Have had fairly good success with PlayOn via Avia. Takes a few tries but eventually works. Can get to Amazon Prime and Hulu (non-Plus) content and hundreds of other channels included or with other playon scripts. Playon can also play local stored content. Will play anything VLC player can render since it uses it.
Would rather see PlayOn directly support Chromecast but this works in meantime.