My new bait tank. Just to give you an idea of the bait tank. To be honest decide where you want it. Then find any plastic container with a tight lid that will fit in that area. If you want a cooler (don't need it with fresh water coming in) then look for a cooler that will fit in the location. BUY IT!! hehehe then every thing else can be made to fit with either cutting or heat. Plastic is so easy to work with. Oh and a couple of ideas for good plastic containers. Pool chlorine table holders (round) and come in 5 gallon increments and more pool places that have a pool service will chuck them. The bucket can be left in the sun open for about a week with water and vinegar in it and the chlorine and smell will be gone. Kitty litter buckets (square) and come in a variety of sizes from 2 to 20 gallons in high and low (wide) styles. The little is great for garages and such and usually cheaper then buying just the plastic container.
For electronics I recommend a good gps but a plotter isn't necessary unless you plan on doing something like hitching a ride to the islands to fish then get a good one. If working the coast I recommend getting a good water proof compass and research the area you plan to fish. If the fog should roll in thick or you get pulled away from your area you can at least get your barrings. I like the gps because if at night you could know where to go or if you need help you can give exact location for yourself and or someone else.
A radio is required by law so get a good one. I am no a fan of the all in one units. If one goes the whole thing is shot or if you loose one you have lost them both but on a yak size matters so all in ones I can under stand. I would not get a fish finder at this point (unless you have the money I am broke hehe) and spend the cash on a good GPS and a hand held. The other stuff will come later. Most likely your going to be fishing kelp anyway and a finder is useless there.