I'll bite: Walleyes on the river will test your patience and dedication, but they're definitely in there and there are some nice fish too, I've personally caught and released a beautiful 27" fat pre spawn female this winter, in addition to plenty of nice fish in the lower 20" range, and keeper males. In one of my hard earned spots, I caught absolutely ZERO walleye this winter, and I hammered them at this same location last winter, so perhaps harvest is taking a slight toll on the fishery. I release most of the walleyes I catch. But, to be fair, I also slammed them good this winter in a new wintering area I discovered. Perhaps the Flathead cats are also having an influence?
Anyways, they can be tough. I'm one of those lunatics that fishes the Susky.....at night......during the Fall and Winter. Reason being that it's effective, plain and simple. As far as locations go, I won't go there, as those are hard earned spots that have taken years of stumbling around in a frozen river to discover, lol. But, by no means is it rocket science, if it looks like a juicy area, it probably is; trust your judgement.
Don't get obsessive about depth. Especially at night, they'll absolutely move up shallow to feed. Most of the eyes I catch are caught in less than 7' FOW. I know the mantra during the winter is to fish slack water, and while I agree with that to an extent, I like moving water, albeit slower current.
I generally go with soft plastic swimbaits or stick baits, but I have gotten them using bucktails. I like them tipped with something. I generally steer clear of bucktails because in some areas the bottom is unmanageably snaggy, but some of the sharpest walleye guys I know swear by the bucktails.
They'll definitely feed during the morning or afternoon, but only under certain conditions in my humble experience. For daylight action, I prefer a river on the rise, overcast and/or raining. If the river cleans up or is low, I stick to fishing at night.
What makes them challenging/rewarding/infuriating, is how picky they can be. If you're not getting bit, do something different. I've literally been slinging a particular lure for a solid half hour, changed to a different color and hammered a fish on my first cast. They're tough!
But most importantly, put in the TIME! Walleye don't care how expensive your waders are or how many hundreds of dollars that G.Loomis rod cost, ultimately it's a game of how intimately you know your quarry and their particular characteristics, and the only way to learn this is to put in the time and the miles. I've become somewhat confident over the years, and I still get humbled some times. But they're definitely in there. Fall is also an excellent time for walleyes, obviously. Be careful in the river during the fall and winter, especially at night. Before I fish a spot at night, I'll fish it during the daylight and get familiar with it, so in the dark I'm stumbling around just a bit less. Good luck.