Saw this a few hours ago and had to chime in! Like someone mentioned, MFT is an option but I honestly have to disagree because Sonys autofocus is just way more reliable for travel. When you are on a once-in-a-lifetime trip, you want to be 100% sure the camera actually locked onto the subject. I love the peace of mind you get with their tracking system... its just fantastic! For your $1500 budget, here is how I would spend the money to stay safe and get the best results:

• Look at the Sony a6700. It uses the bigger Z-style battery so you wont have those power drain issues in the cold that the older models had. Its a total game changer for reliability!
• If you want to save some cash for your actual travel expenses, the Sony a6400 is still amazing and has solid weather sealing which is a must for safety in unpredictable weather.
• Definitely pair it with the Sigma 18-50mm f2.8 DC DN Contemporary. Its tiny, lightweight, and the image quality is just amazing for the price. I really think sticking with Sony is the best move for the autofocus alone. You dont want to be fiddling with focus points while a cool moment passes you by! Seriously, the real-time tracking feels like magic.

I love my Sony a6000. Compact and reliable. Maybe consider professional guidance before buying?

While Sony's APS-C are decent, consider Micro Four Thirds for travel. Smaller lenses, comparable IQ. Had issues with Sony's battery life in cold weather. The Olympus OM-D E-M5 Mark III, though older, offers excellent stabilization and weather sealing – crucial for travel. Unfortunately, Sony's ergonomics aren't always ideal for gloved hands. Consult a photography specialist for personalized advice.