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.

Here's Claude's translation of the PDF in the repo:

https://claude.ai/public/artifacts/0c40c3f8-16de-4947-93c1-3...

I couldn't verify it, and a human translation would be preferable -- but it's probably good enough to get an idea of the story if you want to read some right now.