I did such a trip in winter of 2000 in a Citroen 2CV, around the perimeter of Scandinavia. Because it's up near the North Pole, this region looks small on our projection maps, but our route took us over 3000 miles - equivalent of driving coast to coast in the USA - on ice and snow all the way. The cardinal rule was to stay alive, which meant ALWAYS STAY WITH A BUDDY (no moblie phones) -- both our co-driver AND our buddy car. And we had to have -20 degree sleeping bags in the back seat unpacked and ready to use. Otherwise death from exposure might occur in minutes. So that could reasonably mean to take 2 watches as well.