Just a quick snapshot of the Arithmetic/Logic Unit board before I call it a night. I got all the remaining components roughly placed. When I place components I'm always considering how to route signals, but I expect to have to do a little rearranging when I actually route them.
And there are a lot of signals to route. A ratsnest command reports 1100 airwires, including 326 GND and 135 VDD. Like the Instruction Decode board, this board has a full ground plane on layer 2, but VDD will have to be routed like any other signal.