Kito, The "network" can be as diverse or as simple as you want. At the core, an AP. To that you add the speed and depth inputs, and a wind input, and a display instrument, in the Ray world a version of an i70. Now you can see all kinds of data, apparent wind, true wind, a few thousand variants of speed and depth, every version of velocity known, and a whole schwack (a technical term) of things you never knew you needed.
Add a chart plotter, and suddenly you get the ability to know just exactly where your mooring is, an approach route, where the only marker buoy on the lake is so you don't stick the keel in the dirt, tracking, visual contours of the bottom according to the chart, updated in real time with Navionics+ and the ability to program a route, and have the boat follow it.
Do you use it all on a small lake? Yes and no. Knowing what it does, and how to make it do what you want allows you to leverage the extra "hands" that the AP provides. When "just out sailing" the AP drives most of the time. Setting the response level to "5" (the highest) allows the AP to steer the boat upwind and it won't sway more than about 3-4 degrees off true wind. Nobody can steer that well. (Well, maybe Jackdaw, but I'd give him a run for his money.....) You typically don't sail a route, you motor. You don't motor to the wind input. So you use bits and pieces of the available facilities as needed. That much is no different irrespective of the amount of water around you.
And, when you throw the boat in the "big lake", you don't have to contend with unknown hardware and software, it's second nature.