It looks extremely accessible. I can puzzle through the pages I looked at with school-level Irish.

The script can be mechanically translated to the modern characters, no ambiguity there. The spelling and grammar isn't the perfectly standardized Irish introduced in the 1940s and 50s - which isn't representative of how anyone ever spoke the language - but its differences are those a good to mediocre student might make anyway while trying to write the official standard.

It helps that this is clearly written for a YA audience. Literary Irish has lots of complicated constructions and idioms which are difficult to translate, but this does not.