Two Stories About Patrick That Make Sense

1- He left with 40 others. 
2- He had heard how great it was in America.

In the paragraph below, taken from

THE SCOTS-IRISH
THEIR CHARACTER AND PATTERNS OF MIGRATION by David Strong

We can notice that there were several migrations from Ulster and that large groups and many ships left. I see it as likely Patrick, as claimed by some left with a group. It is also likely that stories of America got back to Ireland.  

Migrations from Ireland: In 1717, more that 5000 Ulstermen left for America. There followed five great waves of migration to the thirteen original American Colonies, in 1717-18; 1725-29; 1740-41; 1754-55; and 1771-75. In the period 1714-1720 alone, some 55 shiploads of immigrants sailed from Ireland to ports in New England.