From what I followed, it came down to two major policies; economy and immigration. And even then no one had a concrete plan or figures. The two sides spent more time arguing about what the other was saying, ramping up the fear mongering and then just letting an uneducated population vote for something they weren't even entirely sure of the in's and out's of.
It would be the likeliest way to go. Since I don't think there's a restriction of United Kingdom movement, so Irish passports would still allow free movement.