Sri Lanka doesn’t really have a good infrastructure for budget travelers at this point. There are loads of nice hotels if you are willing to pay US$40 or more per night, but almost nothing below that except for a few hostels. I haven’t been to Palawan but I have been to Boracay and Palawan can’t be too much cheaper. Boracay doesn’t have many budget options either, so my guess is that Thailand or Cambodia is your best bet.
If you can, try to stay at a hotel or hostel that has a kitchen which guests are allowed to use. You can also elect to find home-share style lodgings, as people often rent out their homes during peak vacation times for tourists to use. Once you have a kitchen, you have control over what you purchase and what you eat. An added benefit of this style of travel, other than the fact that you can stick to your Keto Diet effectively, is that you get to experience the local side of life. Going to grocery stores, choosing from local ingredients, and cooking for yourself will help make you feel like you’re a part of the culture, instead of only a visitor.
We spent a month in Costa Rica last year and although we thoroughly enjoyed the trip, we don’t tend to be “repeat customers”, so we’d like to venture somewhere new (we saw that you had mentioned this as kid-friendly a few times, so just wanted to let you know that we’ve already been there). Some available attractions and activities would be ideal, but, we’d also quite enjoy the beach towns of some sort. We love hostel type of accommodations, aren’t overly-indulgent and can get by on a fairly modest budget. We are of the mind-set that spending more time, is more valuable than spending more money.
Steamed pumpkin sautéed and seasoned with fresh orange juice makes a tasty fall or winter side dish. Pumpkin steamed in the pressure cooker is easy to peel and dice and the steaming liquid can be used as a flavorful liquid in another recipe. You can pressure cook spaghetti squash this way too: use the same timing, but tease out the “spaghetti” flesh with a fork instead of dicing it.
The most important holiday in Japan is oshogatsu (New Year), and the month leading up to it is packed with fun festivals and markets. Standouts are Shimai Kobo (December 21) and Shimai Tenjin (December 25) both of which offer great ceramics and handicraft shopping, in addition to lots of good things to eat and drink. From December 8 through the 17th, thousands of lanterns will be placed around Arashiyama, including in the enchanting bamboo forest. If you’re there on New Year’s, you’ll catch the famous the bell-ringing ceremonies -- get up real early and see the monks at Kyoto’s largest temple, Chion-in, or drop by a small-scale local shrine instead.
Once again, it's worth noting that the first half of December will be cheaper and far less crowded than the time around Christmas, so if it's possible you should come early for best value. Still, compared to, say, Miami Beach, Cancun and the other Mexican resort towns are far cheaper and at least as fun as well. By the way, Cancun is mainly just a strip of high-rise hotels along a lovely beach, while Playa del Carmen (about an hour south) is a real tourist-friendly town with smaller hotels as well as hundreds of restaurants and shops to choose from.