Hi Joe
for ease of communication you can mail me at stpeters@irelandxo.com which is my site mail address. In the 1850s there was a land survey done and you can find it here, http://www.askaboutireland.ie/griffith-valuation/index.xml?action=nameS… each name of landowner / tenant comes with a sheet which when you click pops out and at the bottom you will see a site number such as 20. Then there are two map cons which you can open and enlarge which will show you the plot number 20 and on the top right of the map is a bar which you can drag left and it goes into a modern map to show you were it is if you were touring the area you could find it still, all maps form earliest are here and can be overlaid on each other I understand, see http://www.osi.ie/
The library in Dundalk is the base research library for Louth but it is doubtful they have much pertinant to a specific family that is not online, also the archives for Louth are in Dundalk, again unlikely to have specifics on family. http://www.louthcoco.ie/en/Services/Library/Genealogy-Research-Sources/ and http://www.louthcoco.ie/en/Services/Archives/ I see they seek you to make an appointment a week in advance but if you are of a mind you could give it a try, distance travelled etc.
A very good site for Louth is here and while it has no certs it contains lists of people drawn from various registers over the centuries. You can search the names there, http://www.jbhall.freeservers.com/ Search Wildgoose Lodge murders which was carrie out in your ancestors time in the general area, there was a book released on them some years ago. Migh see some ancestors there. Also in the 1824 to 1838 period there were tithes collected from those of 1 acre or more and the lists are here http://titheapplotmentbooks.nationalarchives.ie/search/tab/ I concentrate on Sharkey as Murray is a name that pops up in each county, have one myself, see on in Cornamucklagh Carlingford too in the tithes.
When in the area there a couple of recommendations to give you in case you have some free time, firstly http://www.newgrange.com/visitor.htm the full tour takes about 3 hours but there are shorter ones if you stick to just one passage grave, you would need transport to get to all these places, there are tour buses and local services. Also I only went here last year for the first time and have been back 3 times, takes maybe anhhour, no charge as it is in use as a graveyard locally but so peaceful and interestng, no charge but donations accepted, say €5 for the two of ye. See http://www.boynevalleytours.com/monasterboice.htm The detail on the crosses is great and a thousand years old plus.
There are other places and if you want more info on hotels etc let me know. Good Luck with the search, appear to be people of those names still in the area you seek, could not find any Lowes in Carlingford but there were some in the recent past I believe.
Enjoy your travels,
Pat