The subtropical climate of Hong Kong means that summers are particularly hot and wet, and spring is warm and humid. November is the sweet spot, with clear, sunny days and mild temperatures. During your trip, you'll want to take a traditional junk boat ride on the harbour (seen here) and check out the sweeping city views from Victoria Peak, which you can reach by tram. Another can't miss? Stockton, a hidden speakeasy-style whiskey bar in Central.
New Zealand will also be crowded, but the country is otherwise mostly empty so it is still wonderful. You could fly to Auckland for one day or so and rent a campervan/motorhome. Drive it for 3 or so days on the North Island, and then onto the ferry to the South Island for the rest of your time. The South Island is far more scenic and less crowded. You’ll be doing some driving and looking, but after a few hours of that you can stop at a campground and have plenty of things to do such as hiking or water sports and much more.
I totally agree about the solo traveling thing being down to luck in many cases. Right now I’m on a long trip around Europe again, and from one night to the next I might meet a bunch of interesting people, or be sitting there alone in a sea of locals with no interest in chatting with foreigners. At least in a place like Goa, everybody is on holiday, so I’ve had good luck meeting people.
Unsurprisingly, the end of December is the beginning of the peak season for resort prices, so those who are able to come earlier in the month will be getting better deals. Still, the all-inclusive resorts are locked in heavy competition all year so this area can be a great deal compared to the alternatives, even in high season. If you are looking for where to go in December for an all-inclusive beach holiday, this is your best option for most people.
Your December plans probably seemed fine until this very moment when you realized they didn’t yet include Reveillon on Copacabana beach -- one of the biggest and best New Year’s Eve parties anywhere in the world. December is summertime here, so you can spend your trip under illuminated palm trees on the beach, before joining two million (yes) other humans for the debauchery of Reveillon. To extend the trip, join a week-long tour that gives you a blend of rainforest, city, and beach.
Mexico’s spectacular Día de Muertos (Day of the Dead), bewitches Mexico City at the start of each November. Donning the skeleton face paint for the mass parades in the main Zócalo square is a must, but take time to step back from the party and seek out more intimate family celebrations where deceased loved ones are honoured with candles, sugar skulls and, of course, tequila. If you’d prefer to relax with a rum, then Barbados in November may be more to your tastes. The sugar-cane liquor is thought to have originated here in the 17th century and continues to be the local tipple of choice. Toasting the sunset from one of the island’s magnificent beaches is a quintessential experience.
Those wanting to hike to Machu Picchu will also find this to be an ideal month, since getting in a group will be easy even without much advance notice. The train to Machu Picchu is expensive year round, and reservations should be easier to get the day before this time of the year. Hotels are always cheap in Cusco so you can afford to get something nicer than you are used to this month.
Unlike most cities on South America's west coast, Buenos Aires has fairly consistent rainfall all year long, and you might see a bit of the wet stuff even during December. Still, the temperatures should be ideal for being outdoors, and this is really mostly an indoor city anyway, so when it does rain you'll be able to pop into a shop or museum or cafe and have a great time.