Well, anywhere along the LIRR Hempstead Branch would offer a quick commute. Here's the schedule:
http://mta.info/lirr/Timetable/Branc...teadBranch.pdf
Jamaica has the N6X bus to Hempstead. (There's also the N6 local, but that would take longer). The schedule is here:
http://www.nicebus.com/_meta/Dec30pd...30Schedule.pdf
If you look in Jamaica, Hollis, or Queens Village, you give yourself the option of either bus. The N6X doesn't stop in Hollis or Queens Village, though (it used to, and there's always the chance they might restore the old limited pattern).
I heard the buses have problems, as far as reliability goes, so you're better off using the train as your primary option. If you just missed your train, you have the option of taking another train to Mineola, and then taking the N40/41 to Hempstead.