Grim, I was going to write a long winded post about how what you're doing is mildly insane, but I wrote something that somehow switched me a bit. So I'll ask this instead.
Have you thought about putting a webcam up at home to keep an eye on your son when you're working? You obviously have time to check up on rpgfan when you're at work, so you have some access to pc fun. If you're interested, check out archerfish. They make ip cameras and have a website that lets you check up on said camera through smartphones, pcs, and most other internet capable devices. I've installed a couple and can tell you they work decently, though you should have at least a broadband connection, and preferably not dsl. At least this way you can check up on him while he's home without annoying him or needing an elaborate setup and camera system. Look into it if you want some reassurance, since the few hours he's home alone are probably your most apprehensive. If you want to be cheaper and have a ps3 and psp, you could leave your ps3 idle for remote play and use the ps3 camera as a semi security camera. Granted, this means bringing your psp to work with you, and only your or your wife can view him at any one time, and it relies on the ps3 being on and connected to the web at all times, as well as having a wifi connection at work you can use. The archerfish camera only requires installation hardware and access to your router, though they make an expensive wifi version too (stay wired).
I hope you can use my suggestion, and that if you had any nervous ticks about your plan still that this may put you at ease.