I presume you mean the GDMBR -Great Divide Mountain Bike Route - the Adventure Cycling route that goes from Banff to Antelope Wells. I've done it over the course of three Septembers, I forget how many days I think around sixty riding days, but the young guys do it in thirty. Most of it is gravel roads - logging roads or old mining roads, or just rural roads. There are a few very rough although short, sections and a few sections of single track. I never saw any tandems on it, there are a sections where you have to push or carry your bike, those are listed in the guidebook and maps, there are usually alternate routes around them.
I would recommend as wide tires as you can mount on your bike, and go as light as you can because there is a lot of climbing, some at fairly high altitudes. High altitudes also can mean severe weather so be prepared for snow and cold. I have never been so cold in my life as coming down from cabin pass in the snow and rain and mud. You don't generate any heat going down hill!
Its hard physically, but not that severe technically and is lots of fun and a great adventure. You will enjoy it.
