I wish I'd taken more pics. I was under the gun to get it done and didn't take any.
From memory...I started by milling both sides flat. I simply screwed the rough cut to a piece of ply (so I could predict where screw holes would be, and be cut out in the end). I didn't program anything but drove the machine manually.
I started on the letter side. The cuts were .5" offsets so the lit letters would "hang" in them. I pocketed the letters using a .25" end mill. I flipped it over using the very precise "Sharpie outline on spoilboard registration" method. I knew I was going to cut the pocket on the back a little over-sized so this wasn't critical.
I then pocketed the back down far enough to get to the letters and was careful to keep the floating parts of the A,R, etc. Those were epoxied on later.
The acrylic was a simple rectangle with the original characters v-carved in .0625". The LED's have a sticky back that I bolstered with the silicone you see in the second pic. Screw it together and get some power to it and ...voila.
I like framing the edge-lits as opposed to plugging them into a base. I can't remember if I ever posted this over here but it's a sign I made for some close friends. They lost their teenage daughter Kirsten a year and a half ago. Fast forward and they remodeled their home to include a small bar. I christened it the K-Club and gave them this to hang over it.
Again, a simple rabbeted frame offset to allow for the LEDS. You can see the assembly in the second pic.