Troll small (4"ish) medium to deep diving wobbling style lures using 8 to 10 pound test line 40 to 50 feet behind your boat at a speed of 1 to 2 mile an hour.
You'll cover more water and increase your chances to catch both walleye and crappy.
As for Musky, no doubt the deeper water, at William, has warmed to the point of sending Mr Toothy to the heavy weeds looking for cooler water with higher oxygen content.
I would think before sun up or after sun down, would increase chances of getting a Tiger in your boat, lobbing musky lures near the shoreline.
Wilhelm as you probably know, sucks when it comes to structure and water depths rarely exceed 15 feet and when it does, doesn't last long. Exception to that rule will be found near the dam (18+ ft) but again, doesn't last.
Just as with any other body of water, there will be those anglers that know where and when to find the fish. Also, there will be those anglers who catch fish while the guy along side catches nothing.
As for me...... stupid fish.
Good times and tight lines.