Dublin: free national museums, the Guinness line, and the cheap bus to the sea

Ireland's national museums in Dublin are free: Archaeology on Kildare Street (the bog bodies and gold), Natural History, and the National Gallery. The Guinness Storehouse is the most visited paid attraction; it's well done and the pint at the top has the view, but book online for a discount and the earliest slot. Trinity's Book of Kells needs a timed ticket. The DART train to Howth or Dalkey gives cliff walks and sea views for a few euros.