OK, figured out the viewport meta code was in the theme header and not being added by the plugin. Updated that and the device-width error went away.
The map is still not displaying in Safari and I don’t see any errors being generated.
Any ideas?
My first thought would be that it’s something related to your theme. I’d try temporarily switching to TwentyTwelve and see if that fixes it.
It looks like you’ve got a relatively large number of placemarks, so you might want to try turning on clustering on the Options page to see if that helps.