The last few years, East Matty has taught me that either I was making a lot of bad assumptions or that the last couple of years, the patterns have just been way off. By that, I mean that where the trout tended to be certain times of year and certain temperature ranges hasn't held true to historical precedent recently. But for winter, you can bet they'll be in at least 5 feet of water or over mud in 3-4 feet of water. The mud option would be best for you in a kayak, since it can be found without paddling out into the middle of the bay. Search maps for "Mary's." It is fairly easily accessed via kayak, though not from the beach. There is mud there and can be some great winter trout.
I would bet money that trout will be hard to come by unless you arrive at the end of a long warm stretch or unless you are willing and prepared to take your kayaks out to deep shell. The last two years, the trout took forever into the spring to get up onto the flats. Two years ago, we were having to fish 5-6 feet of water in early May to catch trout
; there were none up on the flats, at least not that we could find. That is pretty late to me. So I doubt there will be many in 3-4 feet of water.
So, my advice would be to concentrate on redfish. Most of the trails back to the bay from the beach are into back-coves that can be full of reds and your kayak gives you an excellent platform to move thru those coves, bayous and back-lakes that only the skinniest of boats can get to. Not sure what you're used to throwing, but back there, you better be weedless. The Troutsupport lures that Tobin Strickland designed are about as weedless as can be and, rigged weightless, you wont have any problems spooking fish with big splashes. Another excellent bait for hunting reds in those back-lakes and coves are the Buggs Lures. Created by Heath Hippel (a fly-tying expert) and built by hand, they land softly, and even when they are sitting motionless on the bottom, they have some movement; perfect for enticing finicky redfish in shallow, quiet waters. I use the Buggs Curl-Tail Jigs and the Double Bunny Jigs.
Good luck and enjoy!!!