We will have had 4 days in NYC prior to a trip overseas. Upon our return, we arrive at 9:30 PM. We think perhaps we should get a hotel near the airport, and stay 2 nights, with the day in between devoted to Brooklyn. What are our options for getting to & from an airport hotel to Brooklyn, and is that any easier than going back to Manhattan where we will have stayed the first 4 days of our trip?
Thank you in advance !
Jean

A cab will be on the meter. For cost estimates, www.taxifarefinder.com
You can plot public transportation routes at Google maps , citymapper, or the MTA website.

"What are our options for getting to & from an airport hotel to Brooklyn."

Take the A train, basically to and from downtown Brooklyn (Hoyt/Schermerhorn or Jay Street) or to the Heights (High Street - will put you basically on the Brooklyn Heights/DUMBO border). Getting to Park Slope/Prospect Park will take a bit more work - a transfer to the S shuttle or doubling back on a different line, depending upon which side of the park. To get to Williamsburg, your fastest bet may be to take the A into Manhattan because it's express in Brooklyn, change at Fulton Street and take the J over the Williamsburg Bridge (or get the G at Schermerhorn, but that train runs less frequently than just about any other in the city).

Go to MTA | Subway, Bus, Long Island Rail Road, Metro-North for more.

Ultimately, however, regardless of your relative exhaustion you may be better off getting a hotel in Brooklyn and then just traveling back to the airport on your final day.

I use Uber in NY, mostly to/from JFK.