I used this query in overpass turbo:

[out:xml][timeout:25];
// fetch area “Kildare” to search in
{{geocodeArea:County Kildare}}->.searchArea;
// gather results
(way["highway"="tertiary"]["maxspeed"="80"](area.searchArea);
way["highway"="unclassified"]["maxspeed"="80"](area.searchArea);)->.roads;

// print results
(.roads;>;); out meta;

and loaded it directly into Josm, then replaced 80 with 60, and added maxspeed:type=IE:rural as suggested on the talk-ie list, which I hope will make the difference between “rural” local roads, and those at the edge of urban areas, obvious.

I couldn’t find any exceptions listed by Kildare County Council, so I’m reasonably confident I shouldn’t have scooped up any inappropriately, but do shout if I’m wrong.