I made a trip 'outside' this summer... rode to Texas and back over a 1 month period.
I only had about $100 in my pocket at any given time. Used my debit card when cash wasn't feasible.
The cool thing about using a Master Card or Visa Card or any big bank card while riding through Canada (as I assume you'll be doing) is that you don't have to worry about the Exchange Rate... it's all calculated during the billing by your bank.
Carrying large sums of Cash (like I ever have any) always adds to the paranoia that always builds in me when I'm in a region I'm not totally familiar with. And, Canada won't let me bring along my riding partner (XD-45)...
Also, if you are riding the whole trip... Canada's gas stations usually close around 10pm once you get outside of the larger cities... so make plans to stay overnight at the end of each day.
Make note of the earlier post... be sure to "Declare" anything you have on-board... Even though I think the maximum travel cash is $10,000... like on Air Travel, if you get caught up in the "Random" Security Check and they find something you didn't declare... well let's just say a 2-hr delay would be the best outcome.
Send me a PM if you are riding the whole way up here, and I might could share some really nice Hotels/Motels with you and let you know about some of the "Caution" areas along the road.