The US Open is a two-part trip: tennis at Flushing Meadows and New York City everywhere else. For repeated match days, Flushing and the 7 train corridor win; Manhattan works better when sightseeing matters just as much as tennis.
Where to stay
Flushing is the practical choice for repeated match days. Hotels around 39th Avenue and the 7 line shorten the trip to the grounds and make late night-session returns simpler.
Getting to the grounds
Take the 7 train to Mets–Willets Point and walk through Flushing Meadows–Corona Park. Build extra time around security and evening crowds.
Make it a New York trip
Pair Queens match days with Flushing food, the Unisphere and nearby museums, then reserve separate days for Midtown, Central Park, Broadway or the High Line.