If you do this alone, do not tell the missus, because she would be very jealous. The observation deck is the south tower. If you prefer a trip to the park and a stroll before a long haul flight, go to Columbus Circle from Penn Station on the AC or D train, put on your Insect Repellent if it's Mozzy Time and walk up the west edge of Central Park, to the lake with the little humpy back bridge on it. You can get horse and carriage rides in the park, for a considerable consideration. I have yet to try that out.
Buses take forever in the traffic.
The concrete is especially awful on the feet and NYC road department's idea of fixing a hole in the road is to stick a metal plate over it. Ask people to help you if they don't already offer. They will offer. As an English Speaking foreigner, they will love you to bits. There will always be a couple of British tourists wandering around looking for the same thing as you.