The main risk so far with Ghost is running out of memory and the site freezing, so a simple check on whether the site is up with a push alert is enough. There's no traffic to speak of, and no one is reading this.
I found uptimerobot to be a decent start. Their free account will do everything I want at first, and there's no incentive to move to paid for me yet. I'd quite like an app widget that checks if the site is up, but that feels like a project, if I ever get round to it.