I will have a 3 hour connection time between the arrival of my JFK-NRT flight and the departure of my NRT-HKG flights both on UA. Are passengers allowed to exit the United gates to explore other parts of the airport (a) outside security (eg, ticketing lobby or observation deck) and (b) within the secure area but other satellites (NW gates without a NW ticket)? If so, what formalities are there as far as customs/immigration/security screening? And, again if this is allowable, is it advisable with a 3:25pm arrival in NRT and a 6:45pm departure to HKG (i.e., how much time should I budget to get back to the gates from say the ticketing lobby/nonsecure area)? Thanks in advance!