Hi Mary, hope you get some joy on the FB group, and the book gives some information, Darver is the one parish that draws the queries in Louth, the mother of the William Kerr you found is probably Meade now, Meath is county her, adjoins Louth. The other two names are Louth, Durnin is almost always Louth and Lamb is found here too, think there was a query on it awhile ago. This may indicate they knew each other before arrival, if checking shipping records I would also check Carr as the person recording the name may have written Kerr, it is used as a rule of thumb but not to be reli,ed upon that Kerr is Progestant and Carr is RC but do not rely on it.
If you are interested in history, assuming you are in the US, the major maker of "covered wagons" used to go west back in the day was born in Louth, in Drogheda, name of Murphy. I attach a local newspaper piece on it.
In 1852 in nearby Dunleer, in the townlands of Mosstown and Phillipstown, Sir Frederick Foster carried out a survey of his tenants with a view to sending some of them away as the holdings were not viable for all those renting, assisted passage was given to tenants and this is the entry for a Lambe, not.e a Pat Lambe aged 20 and money coming from the US. These Fosters were quiet famous, his brother Vere instigated education for the tenant woman to good effect, there has been pieces written about this initiative which is seen as ahead of its time.
Widow Lambe 61,Pat 20, Judith 22, Michel 15, Supported by labor & by money from America. That is all the entry says.
About 1853 in Louth Griffiths Valuation was carried out, there are 21 Kerrs listed, including a William, some close to Darver, however I also see a William Carr in Darver and a Lamb family, this site has become a little erratic lately but was ok today. http://www.askaboutireland.ie/griffith-valuation/index.xml?action=nameSearch
It is a leap of faith to link these together, it shows families of those names were there and only head of house given and landlord plus maps with plot numbers.
Good Luck,
Pat