Velcro type
Hey Pete, I'd recommend one of the Truxedo, Access, LiteRider type of covers. What is so nice about them is how easy they are to use for one person, and in any temperature. [this will be an issue for you up in the frozen north]
I had and wore out a snap type cover, had it on three different trucks. It was such a pain to get into the bed of the truck, that I took to tying a rope to anything I put in the bed so that I could pull it to the back without having to unsnap the cover, or crawl in.
Now with my Access rollup cover it takes seconds to roll up the cover and retrieve whatever I want from the front of the bed. If you need to use the bed with the cover rolled up, you loose only a few inches of the bed due to the front rail, not a foot or so with some other rollup type covers. I've had this Access cover for over six years and on three different trucks, and it still looks virtually new
They will support over 18" of snow, and not pool rainwater too bad. The only problem I have is the velcro sometimes comes unstuck on the freeway during high airspeed blasts. [90+ mph into headwinds] If I make sure the velcro is fastened real good [run my thumb firmly over the flap] prior to freeway runs, I have no problems.
I sent you a PM.
Hope this helps, Greg L. The Noise Nazi