There are many walk in areas on the south end of the big sac arm. Some of them get TONS of pressure, some of them not so much. Google earth is your friend, and can help you isolate an area you wish to explore. Right now, a big buck could be on any ridge, draw, edge or thicket you can find, they're moving alot. I know where a couple shooters are hanging out, but you'd have to find out where I launch and follow my boat out to get than info out of me.
Everything south of the Y hwy bridge is "anydeer" tag only, no bonus tags may be used. The north end of the lake I have little experience with (north of the 215 bridge) There are still some walk in options up there, but you may have to be creative in parking to avoid really long hikes.
Bout all you can do is get out there and learn, and keep trying. On the bright side, if you get away from most of the pressure, anywhere you decide to set up will be a surprise to the deer, so you'll have lots of "first sit" advantage over and over.
Good luck.