We fish Dyers Bay a lot, although not this year as we haven't made the trip yet :-(. Hard to get better scenery, and the steep drop-off means you can find 100 FOW within 150 yards off shore. You'll often be the only one out there, a 'busy' day might mean 2 or 3 boats nearby.
The bad news is the fishing is slow and the most reliable spots aren't that reliable. Most people focus on 2 areas:
1) troll south from the DB ramp by the 2 cliff 'points' that are just past a rock beach - salmon area. If you're running bait deep be alert, depths can quickly go from 120 to 80 FOW when you're near the cliffs. Some people just circle around those points but I like to keep trolling south along the shore past a stream outflow (near Devil's Monument) which can also produce fish. Never had much luck continuing past that outflow towards Cape Chin.
2) run north from the ramp about 2 miles, look on a chart where Gillies Lake sits above the cliffs - there's an outflow from the lake that you're targeting, good for lakers and sometimes salmon. It's a nice option if you want to zoom from the ramp and take in the scenery at high speed.
If you have it, run a half or full leadcore - that's been our best producer over the years.
Keep in mind winds - anything substantial from the N, NE or E means treacherous launch conditions since the ramp is full exposed to that side of Georgian Bay.
Speaking of the ramp, I don't know if it's open, it had serious storm damage 2 winters ago, they did some makeshift repairs but it might have washed out again this past winter. Check ahead with the township (Northern Bruce) office. Lion's Head gets a lot more traffic and it's fully protected so if weather or ramp conditions are a concern that would be your safest option - I don't have much experience fishing that area but it's also beautiful.
Good luck and enjoy!