Hi Kevin,
It's wonderful that you and your wife are planning a trip over to Ireland. I would be happy to help you out.
To start with, I would encourage you to check out this trip idea "
Around Ireland in 12 days". This tour would take you right around the island and you would get to see a wide range of incredible sights in both the Republic of Ireland and Northern Ireland. For more inspiration on what to see and do when in Ireland, you can check out 
this page.
For more information on ferries, have a look at 
this page. You can learn more about renting a car in Ireland 
here. For general information and advice on traveling to Ireland, you can check out this 
Ultimate Guide.
I hope this information will be of use to you.
Regards,
Eoin