Honestly I don't know how you would connect up families without parish records and the ability to go through the originals, its very difficult. I was fortunate when I traced my husband's family in Wicklow as they were Church of Ireland and all the original registers are kept at their own Library in Dublin after 1890 they are in local custody. Whereas the RC records are in local custody but with microfilm at the National Library in Dublin which you have to research in person or pay a person to do it for you. I only got back to 1813 as the records before that were destroyed in 1798 then those up to 1811 were spoiled by water it looked like.
I never found the marriage of the 1813's parents or their birth records as they were recorded in the wrong parish, just next parish the records exist back to late 1600. Its just the luck of the draw.
I know www.familysearch.org
did have the RC records prior to 1864 but when they changed their website I haven't had any luck since. You could try going to the above website, then instead of filling in the on line form, scroll down to Ireland and the UK, click on that and scroll down again till you get to the records dated 1620-1881. Also the IGI is in that list and that is where the Parish records used to be.