Technical advice please

I am about to travel a long way north to 23 hours a day of darkness (with snow to reflect light). Which camera should I take?

1. Nikon D5100. Disadvantage: I don't know it very well and haven't used it for quite a while. Advantage: I have an f1.8 prime lens (35mm) and a 55-200 zoom (f4-5.6).

2. Olympus Em5ii with a 14-150 zoom (f4-5.6). I know it well and can adjust settings quickly.

Both cameras go up to ISO 25600.

Sorry for my scant presence here recently. Preparing for the trip, tying up loose ends at work and celebrating a family birthday today have pushed photography a long way down the list.