George Douglas in Griffiths 1854 if your George lived in the Parish of Rathcore, Townland of Rahinstown, Poor Law Union of Trim (the Union would cover an area with towns/villages/parish's in a 12 mi. radius)Tenant of Robert Fowler

#1 Richard Douglas land 21 acres 3 roods 7 perches - no house so he must live elsewhere*
#2a George Douglas, house, outbuildings and land 118.0.37
this is a significant size property for the time, the rental per year would of been quite high, I don't see any renters/occupiers providing him with an income.

*Richard Douglas, Parish Athboy, Stocks Townland tenant of the Earl of Darnley, PLU Trim. property house, outbuildings and 5a 202.2.23 another extremely large property as the average person would have maybe 20- acres.

There were 18 Douglas occupiers in Meath at this time 1854 none were Aaron (he may have still been living with his father and helping run the farm but not have property in his own name, he may have not been the oldest son and chose to go to Auz. to make his own fortune? However, this is just at the end of one of the worst Famines in Irish History)

Directories:

1881 & 1898

Daniel Douglas, Stocks, Athboy, Trim, farmer he is listed under farmer but also under Nobility, Gentry & Clergy, he isn't nobility-no title nor Clergy ie Rev.therefore part of the Gentry/Esquire class as noted above who have land that is rented out for income.
1894:
Daniel Douglas, Cherryvalley, farmer
Richard Douglas, Rathmoylan, farmer
William Douglas, Isaacstown, farmer

Trim was a market town and assize town 2 mi. N.W. of Dublin, 11 s.w. of Navan and 6 mi. s.e. of Athboy and was the Civil Registration District/Poor Law Union

Meath belongs to a not for profit Irish History Foundation which operates a database for most Irish County Geneology offices. It is a voucher pay system, until this April you could look for free and get a birth year and name and then purchase a record this has now changed to even a charge of .10 Euro to look. 1E is currently about $1.40. Since your Aaron would only have a parish record at this time this is probably your best bet for records. The National Library has microfilm of Parish's records and the Latter Day Saints have microfilmed the NLI records and you can order in any microfilm to your closest LDS Heritage Center.

Resources:
www.censusfinder.com United Kingdom+Ireland+County
www.igp-web.com + county these two website have varying amounts of information depening on the county

Annette Code
ps are the Douglas Protestant as the name is so English and certainly the property sizes are indicative of this, if so
there is another option for parish records and that is the
Representative Library of the Church of Ireland who have the parish registers to 1899.