Any cut off the ICW going from the Freeport Harbor is good in either direction. I’ve fished from Cedar Lake Creek to up to Bastrop Bayou, every cut will have fish in it. Some are creeks, some are bayous, some lead to lakes or bays. Look for moving water next to oyster shell. I like to stake out and probe those areas with something that sinks. A lead head jig with a paddle tail. I like to bump these off the bottom which means getting hung up. Suspend gulp under a cork might help the hanging up. I just learn to manage my retrieve to minimize hang ups.
Sounds like you know about the cuts with the flounder catches. Every little system has fish, but it doesn’t mean you are going to get on them every time. High water levels spread out the fish, low water levels concentrate fish. .5 MLLW or less is what I’m calling low, 1.8 MLLW and above is high. In high water, I’m normally looking for water flowing over and around bars and reefs and choke points rather than chasing fish way up in flooded grass. In low water, I’m looking to find them in some drain, but they are rarely evenly distributed. The whole NOAA system will have the water levels. The Freeport USCG station is the chief one I look at. https://tidesandcurrents.noaa.gov/stati ... id=8772447
But if I had one option, I’d have some soft plastic on a jig head. Look for bait doing things that seem to indicate that something is influencing them. Fish intentionally. Drifting isn’t bad, but set up the drift knowing something about the structure. Fish orient themselves to structure and it can be subtle.
In general, redfish tend to be in the smaller, more shallow systems. There could be some flounder and trout, but redfish seem to rule small shallow marshes. A bigger system like Cow Trap might have all three. An even bigger area like Drum Bay or Bastrop Bay will definitely have all three. It’s my belief the Fish use the ICW as a highway. Something might push them out of one place, a lot of fresh water runoff for one, and move the fish around to another system. Some places are better than others at different times of the year.
The surf is a great idea, but often it gets pretty chewed up by chop. That is why I would carry a kayak on some planned surf wading outings, although, I’ve gotten pretty good at knowing, from buoy data, when the surf will be wade worthy. The jetty is another idea. I’m not a big fan of crowd fishing so the jetty is usually not my thing. There’s tons of water around Surfside that’s marsh and great for a kayak. Pick a spot with a reef and work it. Or find a gut and work it. Or a drop off and try that. Move around if you like. I’ll move around often on the same structure looking for the sweet spot. Don’t say” well, I’ve stopped on one spot on a 1,000 foot reef and there was nothing so the fish must not be here”. I’ll move multiple times if the signs look right trying to get on the Fish.
I lived at Surfside for 3 plus years and have fished there for 12 plus continuously. There’s great water all around. There’s great water up and down our coast. You will have zero fish days and there’s potential for catching fish until you tire of catching them. The fish move around. There’s no set formula other than getting out there.