If you don't want to deal with the luggage and trains or subway and airtrain, you can take a cab to the airport, they will pick you up at the hotel and drop you off at the terminal.

The decision to visit for New Years Eve of course depends on if you want to be part of the crowd and think that's a cool thing, or if you don't want to be anywhere near the masses of people because you think it's a dumb thing. It's totally up to you.

Street closures, in the past, have been as listed below.

At approximately 1:30 p.m. on Monday, December 31st, the following streets will be closed to all vehicular traffic:

Seventh Avenue, from 41st to 59th Streets;
Broadway, from 47th to 59th Streets;
43rd to 47th Streets, from Sixth to Eighth Avenue.

Beginning at 5 p.m. on Monday, December 31st,
42nd Street from 6th to Eight Avenue will be closed to traffic.

After 6:30 p.m. on Monday, December 31st, the remainder of the traffic closures will be instituted as crowd conditions warrant:
All cross-town streets from 37th to 41st Streets - Sixth to Eighth Avenues;
All cross-town streets from 49th to 59th Streets - Sixth to Eighth Avenues;
48th Street, from Fifth to Ninth Avenues;
Cross-town access for emergency vehicles will be available on 42nd, 48th, and 59th Streets.

I don't believe any streets in the area of Penn Station, until you get very close to Times Square, are closed to pedestrians, and certainly nothing as early as 4. Subways usually don't start skipping the Times Square Stations until 7.

Indeed, there's usually a New Years Eve concert at the Garden, and those people certainly don't have to be in by 4 to get to it.