Yup. Hunted right where those circles are. Having a bit of experience with the causeway I'll give you a few tips
Kayak is a long walk. Go out there and see if you really want to haul a kayak all that way. The camps/houses along the other shore used to marked with no parking, lake access signs, etc.. so not likely you will get them to let you drive out to the waterline.
Bike with a big duffell that will fit your waders and 1/2 doz dekes will get you there and back without working up a sweat.
The island...some years you can walk to it in waders (most years). There can be some good shooting off the shallow point closest to the causeway. Only thing out there is an old falling apart camp. A lot of the light areas in your pic is actually sand bar, it gets pretty shallow through there, yet not as much by the shore
The circled shore area has some years little pot holes in the grass. Check those out, the bottom is pretty decent for retrieving with waders as long as the water stays somewhat low. SHould be pretty good now, but when it gets back near 98-99 feet not so good.
If you walk, don't carry a lot of gear in June the parking lot to the causeway isn't that far. Its 2x further in late october with a bunch of gear. There are some guys that go out there with a garden wagon to carry their stuff.
If you look along the rocks there used to be rock blinds built along the casueway to hunt from.
Carefull how far south you go, some of the area you are looking at may fall into the Winooski Valley Park District. No hunting. They even say no firearms, but have no authority for that.
Good luck, might see you out there.
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