Flights from Dublin are already on sale, and Summer fares have already shot up. For the route I would want to take (to Houston), I wouldn't save much at all in summer, and definitely not enough to justify the inconvenience of making the road connection from (say Providence to Boston) at my own time and expense. Looking ahead to Christmas 2017, on the other hand, the quoted fares are looking really good. It's too soon for me to confirm I'll be visiting the USA, though.
Regarding your Xmas '17 planning - if you don't mind switching flights, you'd probably save a few bob jumping on a low fare to Gatwick then Westjet to Montreal or Toronto then Jet Blue down to Houston. Know it's a bit of switching but if slots aligned you could save a tidy sum over the Shamrock usual gorgement.