1) Northern Kingfish are very similar to the southern kingfish. I have fished for them and they are fun enough. Locals love to catch and eat them. They are maybe a foot or s in size. Small piece of bloodworm on a # 4 hook in shallow water near a drop off should do the trick. Last 2 hours of the incoming and 1st 2 of the outgoing are good tides. If you are near Wildwood at all check the Hereford Inlet area or Grassy Sound for them.
2) Sea Robins -- In my experience the # 1 way to catch them is to use a chartreuse Berkley Gulp on a lead head (4 "swimming shad or grub) on any tide in pretty much any water. They are all over so they should not be too much of a challenge. Anywhere near a drop off or creek inlet should increase your odds. You will catch them if you soak bait such as squid too.
3) Oyster toads -- just soak some bait in areas where the fish may like to hang out, any structure at all will hold them. The Delaware bay is littered with them,
I hope I didn't dissuade your thinking about a yak too much! I love the whole concepts...finding little spots often overlooked, exploring,etc. If my home lake wasn't so infested with yakkers and boats already I might have held onto it. Get one that works for you and have fun with it!
A couple of years ago I bought a completely tricked out sit in top (SOT) fishing Kayak a Tarpon 12 footer. I had all the bells and whistles....anchor trolley system, fishfinder, three rod holders, 2 dry storage areas, the works. It had a wide beam and tracked very well in the water. The thing was top notch and I could not wait to use it as I was completely in love with the idea of slipping into little nooks and sneaking up on unsuspecting fish. I am all about stealth mode fishing.
I used it twice before selling it.
In my excitement of getting one I didn't take a step back and think it through, but in hindsight I can sum it up by saying I got rid of it for the same reason I sold my boat even longer ago. Using either the boat or the yak, for me at least, started to turn something fun into more of a chore. I am not trying to be a downer but thought I would share my experience for perspective. With the boat I did not have a slip or place to dock it, so every time I wanted to use it I had to load the boat up with gear, trailer it to somewhere, wait in line to launch, stress through the launch process, then, finally, fish. Once I finished fishing I had to reverse that entire process. Over time I found that to take away from the enjoyment that fishing brought me and the "work" factor became just not worth it for me.
The kayak experience was similar for me, but not the same. I still had to load the thing on my roof and tie it down to start with. Not an easy task with an SUV when one is not exactly tall . I actually hurt myself quite badly and left heavy scratches in my car loading it once. If you get a Yak, make sure you can lift it for loading onto a car. Without the add ons, my Yak weighed about 60 pounds or so. The anchor system, while neat, required perfect positioning for placing on the roof of my car. Then tying it down securely, getting it to the water, etc. again just started to turn fishing more into work. I rarely have more than a few hours to fish at any given point in time, so I think you can understand why the add on work items started to become irritating. More time fiddling with stuff turned into less time on the water.
What set me over with the Yak was the wind. I generally fish lakes (especially Marsh Creek since it is close). I did not realize what a pita the wind could be on open water when trying to fish. Staying in a given area was brutal with any wind, even with the anchor set up (which in a wind just turned it into a merry go round). Casting lures from a sitting position and being so close to the water surface was also an issue to the point of the advantage of moving quickly from spot to spot was offset by how limited my range had become while so close to the surface.
Just my .02 based on my experience. Would I get one again? Probably. It would have to be the right setup, such as the Hobie with mirage drive and I would need a better way off getting one off and on my vehicle without scratching the car or busting a nut.