Those last two aren't fool proof - someone skilled and persistent enough could still slip in, but most anyone just looking for free access will look elsewhere. If they're still getting in after all this, then you're going to have more success talking to them than any technological solution on a normal home router.
just do the WPA. That will do the trick. I also limited mine to like 6 addresses (I have now pushed it to 8 with phones and tablets and itouches and rokus). I use a simple password that is hard to guess so I can tell people who come over if they want access. and I check it from time to time
We'll be back right after order has been restored here in the Omni Center.
That the universe was formed by a fortuitous concourse of atoms, I will no more believe than that the accidental jumbling of the alphabet would fall into a most ingenious treatise of philosophy - Swift
This is a sample I used in some VBA code embedded in an Excel spreadsheet. This line checked if the cell value was blank. You could use the line in an "If-then" setup to set the .value parameter to the random number. Sheet#.Cells(X, Y).