All great ideas above. Here is my two cents. I'm not an electrical expert, either, so I had to dumb it down for myself before I could move forward, thanks to the help from several forum members.
I bought and made a simple 12 volt DC transformer based on the forum experts (including tips from some of the guys here). I cut off an old cord from an old device for the cord. You must get the polarity right, + and -, with DC. I used a Lionel transformer and a voltmeter with wires to test each wire on the cord in order to know which color wire belonged to each prong on the old cord (the wires had multi-colors). You can also use a 10 -18 volt bulb instead of a voltmeter. I then connected the cord to the transformer I bought on EBay (transformer pic with terminals connected is from another forum member). Then, like ScoutingDad says above, you can cut the LEDs and connect them via soldered wires to the transformer. You can also buy 12 volt DC LEDs with black/red wires on EBay (in my transformer picture) for individual bulbs. I built a box for the transformer to make it a little more safe so I can hide the terminals for the wires that plug into my house outlet. This gives a full 360 watts of 12 volt DC power. You can also add a digital 12 volt DC meter to test the output. For added appeal, this 12 volt transformer then allows you to also power other 12 volt DC accessories like the Hamburger shop building pictured that I also bought on EBay.
