You said DIY is preferable, so are you bringing your own rods? If so, you can probably catch some mangroves off the Venice pier pretty easily with some cut bait (threadfins/herring). This is about 15 miles south of Siesta Key.
For snook, redfish, and trout (which are all closed season until May 2021 at earliest, but you can catch and release, you will need a kayak to get to those in the intercoastal. Let me know if you rent a kayak and I can tell you where to put in. For that you would be tossing artificials.
If you want to just make it easy on yourself and get a guide, contact CB's.....they have a whole team of Captains that can put you on the fish in short order.
DIY sounds cool, but there is no substitute for well presented lively baits on the best spots, which down there is hard to do unless you are in a boat with a livewell, and know the area.
PS - Harbor Springs, and northern MI in general, is one of my favorite places on the planet.