Hi Julie, 
Yes you can - both the New York by night and Capr Cod excursions can be pre-booked before you leave the UK (alternatively they can also be booked with your Tour Manager).  
New York by night - £35 
A fantastic opportunity to see the great sights of Manhattan Island illuminated! During your tour of the city you'll also visit Times Square to view the lights followed by a trip up the Empire State Building for magnificent views of the Big Apple. 
Cape Cod - £37 
Join our exciting tour to beautiful Cape Cod. Renowned for its up-market coastal resorts, Cape Cod's shores are a playground for the rich & famous. Including visits to Plymouth, where America’s founding fathers first set foot in the New World, and Chatham to see its lighthouse. A stop is also made in the village of Sandwich, where you may wish to drink from the ‘fountain of youth’! 
I hope all of this information helps. 
Kindest regards, 
Julia