Hi, I recently went on a few trails in Vancouver, Burnaby and Surrey.(I'm not sure what is "fat trail") There is also one in Coquitlam but that my next target for a trip, but I injured myself during the last trip. (A god damn truck moved into my bike lane to right turn and he/she didn't shoulder check for cyclist, so my choice is hit the truck or just fall to the sidewalk, so I chose the second in the split second. Too bad it didn't see the plate number or the company the truck belong to. Surrey seem to me is bad place to bike because fewer bikers result in drivers lack of attention)
Anyway, Vancouver has by far the best one to my experience. Riding along the seawall with awesome scenery and summer breeze. It says officially to be a 22km route, but you can go a lot further if you go from waterfront station all the way to UBC. (I didn't go beyond UBC, but after kitsilano beach it's almost entirely unpaved gravel ground, you have to share a road with cars if you want paved)
Burnaby is a long one (called central valley green way), all the way from New westminister to downtown Vancouver. But most of it is sharing road with cars and the isolated greenway is pretty terrible considering it's all gravel. So it's not really a trail..
Surrey is all little segments of trails and then you have to ride with cars for a few blocks then find another trail. All different names too, so I don't want to list.
But on snow? we barely have snow here...like once or twice a year. There are not deep either.