The advice to use non-ethanol gas in the winter (actually year-round) is good. You can find the nearest source at
www.pure-gas.org. If there's a marina near you with a fueling dock, that's a very good place to find it.
Ethanol does absolutely nothing good for your engine, winter or summer. Among its many drawbacks (lower energy content, for instance) ethanol is hydrophilic, which is a fancy way of saying that it attracts water. I shouldn't have to explain that attracting water into your fuel system ain't a good idea.
Switching to a multi-vis motor oil is also a good idea. And I would suggest a careful setting of the valve lash in the fall as part of your regular winter prep maintenance. If the lash is off just a couple thousandths, it can disable the partial compression-release system that is built into these engines, making starting MUCH more difficult in any weather.