In Central America you could consider Belize. It’s small, but it’s got islands and beaches (not everywhere though) and forests and other cultural sights, and English is more or less the official language. It’s not as well organized as Costa Rica, but it’s not bad and it feels safe. The other to consider there is Panama, which obviously has a lot in common with Costa Rica. It has far fewer adventure activities and the good beaches are spaced out a bit, but still it’s a relatively rich country with tens of thousands of Americans and Canadians living there as well as visiting, so they have a good tourist infrastructure and it’s safe.
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.
Those countries are all very safe, and especially that time of year, you’ll be surrounded by dozens of other backpackers everywhere you go, including many solo ladies or girls in pairs. There is very little petty crime there, although it’s always wise to keep track of your belongings. It’ll be easy once you get there, and Bangkok is the perfect place to start. You can book a place near the famous “backpacker ghetto” of Khao San Road, which is quite affordable and really fun, as well as close to the top sights.
Keep Snacks Handy When You are Out – This was my snack stash for Disney World. I had Macadamia Nuts, Walnuts, Pecans, and low carb bars. I made sure to chill the water bottles in the freezer beforehand so that as they thawed throughout the day, we had cold water. When hunger hit, instead of falling to temptation, I just grabbed my bag of snacks before I got HANGRY. Doing so made it so much easier to make keto/low carb choices at mealtime. I kept my snacks simple because we already had enough to bring with us (if you have a baby and a toddler you know what I mean). I saw lots of people with small coolers who were snacking on fresh veggies and deli meats, but, again, my goal was easy breezy. You can find a great list of Keto/Low Carb Snack ideas here for inspiration if you prefer a variety.
Without knowing more about your interests, my top suggestion would be to focus on Sydney and Melbourne and the areas around both. The Blue Mountains near Sydney are also nice for a couple days or so. The main challenge you’d have in seeing a lot of Australia is that it’s all so spread out. You can hire a car for Melbourne and Sydney and that whole area, but it’s better to fly to get to Uluru (near Alice Springs) or Brisbane or Cairns/Great Barrier Reef or Perth. You’d be driving for days in between those places if you started from the southeast area where most people live.
Thank you, and I’ll be happy to try to help. But first I have to mention that ALL of Europe is quite cold in December and there are no beaches that are anywhere near warm enough to even spend time on, much less go swimming. The only place that could possibly fit the bill is the Canary Islands, which is off the northern coast of Africa although technically part of Spain. It’s reasonably warm there during December, and there is quite a bit to do.
Plan ahead. Research a little on supermarkets if you’re self catering and restaurants if you’re not. Luckily we’re both a little bit familiar with Italy so we knew we would be able to get plenty of keto food without too much searching. I did have an issue with chocolate though. I ran out of my Lindt 90% and didn’t bring any with me so I had to hunt a bit to find a grocery store that stocked it. Most shops only sold milk chocolate.
By early December the rainy season is pretty much over in Cartagena, and it cools down just a bit more as well, so the weather really doesn't get any better than this. As with most others on this list, right around Christmas you'll find that hotels get more expensive and are more crowded, so if you can go earlier in the month you'll be paying less and dealing with fewer crowds.
That said, I think going to Siem Reap in Cambodia would also be a great idea. And Vietnam is also really wonderful, especially that time of year. Hanoi is quite chilly in December and Saigon is still very warm. It’s worth visiting both of those along with Halong Bay near Hanoi and Hoi An in the center of the country on your way between them. You could easily spend 10 days in Vietnam or more.
I’ve spent a few weeks on Boracay, but not in early November. From what I’ve read, the monsoons there are usually not too bad, and it’s mainly a matter of a couple of hours rain in the afternoon on the bad days. Throughout the Tropics it’s very rare to get rain all day on any given day, and I’ve spent many months in those areas during rainy seasons. So early November isn’t ideal, but if it’s the only time you can go I still think you’ll enjoy it. One nice thing about Boracay is that the hotels are all basically on the beach or right off the beach, so even if it does start raining you can be back in your room in like 2 or 3 minutes. Best of luck with this. -Roger
If the thought of another year crawling to a close has left you feeling a little low, November is the perfect time to give yourself a travel-fuelled lift, with an array of destinations primed for exploration during the penultimate month of the year. Trek in perfect conditions in Ethiopia and Nepal, visit Orlando’s theme parks at discount rates, sample an unusual Thanksgiving dinner in Puerto Rico or don your skeleton outfit for Día de Muertos in Mexico – trust us, the year is far from over!
New Zealand is an excellent option in December, as it’s before the Christmas crowds and just before the summer holidays there. The best and most popular way to explore New Zealand is to rent a camper van or a car and drive from one “holiday park” to another. Auckland is a pretty generic city so it’s not worth spending more than 1 or maybe 2 days there. Just fly in, and rent a vehicle to leave the next morning, and drive south. The North Island has a lot to see, but the South Island is even more scenic and pleasant. You can take a ferry between the two with your vehicle.
If you’re a bit more on the timid side, you can always use Yelp and TripAdvisor to get good insights on places people have visited. As a disclaimer, some of the ratings may not be accurate on these sites, so make sure you go through and read some of the more recent reviews that people have written. We did this for a few of the places we visited and had no issues.