Persistent over/under voltage was always my challenge traveling. A surge protective device doesn't do anything when power is running at 300V for a few seconds. The old MOVs, without proper fusing, would always pop and start smoking, which was a sign to trip the main breaker before everything got fried.
For truly sensitive electronics we always used commodity 12V chargers tied to a big battery bank with individual inverters for each piece of equipment. We might have had a custom filter to deal with ripple current off the chargers, too long ago to remember the details. The chargers lasted 2-3 months on average, but were easy to replace. Normal dual-conversion UPSs would barely last 3-4 months and were much harder to find and more expensive.
For today, I would have two laptop power supplies and an extra battery, and only charge from USB. The bigger USB power supplies are pretty robust, worth carrying extras.