Hey there,
Dan is correct, my wife and i bought our Gateway 3500RE last november and had to use it for a family emergency in Spokane during December through February in temps well below freezing and 20 below for close to 2 weeks so got a crash course on cold weather use. The biggest issue we had were the low point drains, ice wicked up the lines from them and froze the feed lines, Dan helped me with that problem by building boxs out of 1 inch foam board insulation and putting heaters inside to thaw the lines out, after that we had no more problems and now would and do not have any problem.using the Gateway in any weather, there are pictures posted from last winters experience.
If you have any questions please do not hesitate to send an email.
Marcus