I drive regularly to Galway and have a love/hate relationship with the M6. It has certainly saved me a lot of time but I find it soooo boring. On top of that there aren't many geocaches along the route. As a result I decided to set up a series along it to provide drivers with a break and to make the journey a bit more interesting. None of the hides will be particularly difficult or exciting but at least you can stretch your legs. There will be no room for swaps. I skipped Athlone.
You are looking for a magnetic nano.