In addition to the other good recommendations, a multi-fuel stove (I have long used the MSR XGK) and bottle since it can use AvGas or Jet Fuel and you don't have to carry fuel.

Good science has shown that bringing water to a boil will kill all the bugs. You don't need to keep it boiling for any time (especially at or near sea level). There of lots of comments that come from older sources around that recommend longer times.

If you use a good filter (I have used a Katadyn Pocket Filter for many years) and viruses are a problem in the area, a little chlorine (I usually use SweetWater) and 5 min will fix the problem. Fast and so little chlorine that I can't taste it.

The MIOX and SteriPen are both good options. All of the above have their strong and weak points, you should choose the one that is best for your situation. I have and use them all.

The best,

Jerry