Hi Geary- welcome the the forum. Looks like you are off to a good start. Since you've never had trains, keeping it simple to start is a good idea. The wiring for basic loop running is simple. Just make sure you have several drops connected to prevent voltage drop.
I would drill the holes bigger while you can. As the layout grows, the wiring will as well, exponentially! Larger holes will make pulling wires easier, especially when working under the layout.
What kind of locos and rolling stock will you be running?
Keep us posted as you go. Don't be shy to ask questions if you get stuck.
Bob
