Step 1: Mapping out the Space
The piece of acrylic I bought was just smaller than what I really wanted, but it does the trick.
Step 2: Mark the intersections
Step 3: Lay out the troughs for the roads
Lessons learned working the acrylic
I am using a router with a 1/4 inch bit. I initially ran it at full speed but the acrylic melts easily and was just gumming up. I had an speed adjuster around that you can put between the plug and the outlet. There was a lot less gumming up with a slower speed.
The cuts were cleanest if I started in the center and rolled the router along the fence to the edges, taking off another layer with each sweep until I had the full depth (about half the thickness of the acrylic). I eased out of the trough in the middle as well since stopping at the ends left that part all uneven.