Lots of good fishing both north, south and west of CR 40 ramp at Yankeetown.
For Trout and Reds, I personally recommend running out to the 'bird rack' (Withalocoochee River Channel Marker #9), then turn right and run about 5 miles on a heading of 340 degrees. (careful making the turn just past the rack...lots of rocks). This will put you smack in the middle of the 'grass flats', just west of Lowes Bay.
Depending on time of year and time of day, adjust the water depth you're fishing in. Generally speaking for Trout, the hotter the water, the deeper the fish are. Once you figure out the depth, the rest is easy. Best bet is to drift. On a good day the wind/tide will work in your favor. Typically, I'll let the boat drift as long as we're maintaining the depth the fish are biting at. NW and SW winds work best. Make several short drifts if the wind/tide doesn't cooperate. Maintaining that depth is the trick to big Trout and big numbers.
As to the tackle, nothing beats a Cajun Thunder for Trout. I've never seen anything like it. Like shiners for Bass, you either got a Cajun Thunder, or you need one. For the Redfish, simply run due east from the flats and fish the skinny water around the oyster bars. Best bet is cut mullett or shrimp.
As always use caution when out on any body of water, especially the unfamiliar...