Matt_Stevens said:

I'm assuming I can just make my own DVD5 from the AVCHD or MKV.

Yes, however if making a DVD yourself, the mkv is the better source due to the higher bitrate than AVCHD.

If Bluray equipment is available, eschew the DVD for a proper Bluray created from the mkv using either ClownBD or TsMuxer. You can select which soundtracks to include out of the large number available and which to make the default selection, to make playback easier, since there won't be menus.

If you really want menus and to include say the documentary or any other video on the same disc, you can use MultiAVCHD, but it has a relatively steep learning curve.