The video stream alone is 12.7GB (and with good reason), so no DVD-R is going to hold this.

At a push you might convert the MKV to a BD folder using TSMuxer, then use BDRebuilder to 'shrink' it to DVD-9 size. It's a clumsy way to do it, though - better to wait for the official AVCHD release (since that smaller version will be directly encoded from source).

I'm having fun trying to get Adobe Encore to import the video stream without crashing. I'm not sure the designers of this software even considered feature film file sizes when they put it together...