Publishing offline for viewing course on a tablet

I am desperately in need of a fix. I would like to publish a course that can then be loaded onto a tablet (probably Android but happy for suggestions for ipad etc) and accessed offline. 

With the demise of the Articulate player, I can't find a recent post about how to make this work. Closest I have got so far is putting storyline output folder onto an SD card, inserting that into a tablet, then attempting to open the .story file (as you would if you published locally for HTML on a desktop)

It opens in the tablets browser but then the loading icon spins indefinitely in the centre of the screen.

Any help appreciated, my client would love the course to be tablet based but needs it in the field with no internet connection!