As someone who lives in a 'prescribed northern zone', I can say that the travel deduction that Tim talks about is not a universal one available to everyone in a prescribed northern zone. 

From form T2222, "You can claim a deduction for other travel (vacation or family reasons) if you have an amount in box 32 of your T4 slip or box 028 of your T4A slip showing any taxable travel benefits you received in the year. You can claim a maximum of two trips per year for other travel for each member of your household."

From personal experience I can tell you that probably less than half of residents living in a prescribed northern zone will have an amount put on box 32 of their T4.  Many employers have been burned and have had to repay substantial amounts to the CRA for trying to give their employees this benefit.  This is a personal issue with me as the rules for this benefit have to be made more transparent. My current employer refuses to offer this benefit for this very reason.