Check out Barrowline Cruisers www.barrowline.com They are based in Vicarstown, on the Grand Canal/Barrow Line and are the nearest barge hire company to the River Barrow. Vicarstown is only two hours away by boat to Athy, which is where the canal meets the Barrow River.
The Grand Canal passes through Dublin, Kildare, Laois and Offaly. You will pass through countryside not accessible in any other way. It offers scenic landscape of ancient bogland, farmland, forest and hills. It's a beautiful old canal with elegant stone bridges and locks. There are towns and villages every couple of hours along the way. So you have a choice of both worlds. There are taxis in every town and village for your excursions. There are also train stations in some of the towns along the way. For your excursions, if you take the Grand Canal route you could take a taxi to Emo Court or the Japanese Gardens in Kildare Town. You would pass through Tullamore where you have Tullamore Dew Heritage Centre. You could also take a train to Dublin to see the sights.
The Barrow River is also very scenic, uncrowded and unspoilt with its tree-lined valleys. There are towns and villages every couple of hours along the way also. In Athy you have the Athy Heritage Centre www.athyheritagecentre-museum.ie/ Carlow also has loads to offer http://www.carlowtourism.com/
Take a taxi to Kilkenny city to see Kilkenny castle. There are so many things to do and see along the Grand Canal and River Barrow, I'm sure you would love it.