I've been planning a trip to the central part of your route, and I'm also put off by the extreme conditions. The snow, I can deal with. The big problem will be the stream crossings, since the water is so high and so cold.
1) In many places, the trail will be underneath feet of snow. However, if you have never been a GPS user, it would be too much to expect to just pick up a GPS receiver and have it guide you over the snow. You probably don't have an accurate set of waypoints to punch into the receiver. GPS receivers are not good for guiding you ten feet this way or ten feet that way. They are excellent for locating a spot within 50-100 feet.
2) Bear spray? No, you don't need bear spray. I carry it when I am on the trail in grizzly country, but black bears are not that aggressive. Black bears are more like sneak thieves. If your food is inside a bear canister, then you don't need to worry about bear attack.
3) Fishing? Are you talking about ice fishing?