In your case, I'd consider bringing it to the farm while you are away. Make it easier on the one that would have to come around to feed/water it. Cats are social also, they need interaction or they'll leave and find there own. Farm should be warm and cat'll have companionship/interaction.

Also, should consider worming cat - if it is a mouser / chipmonkier - it'll have parisites. This time of year, a good worming and cats have lessor diets of rodents and more cat food, it'll fatten up nicely to make it though the winter.