Taking suggestions here on the board and elsewhere, here is what I did. I purchased a two spout draft tower, because I can only think I will continue to drink only one beer at a time. I also purchased and cleaned the heck out of a second keg. Deep well sockets for the win. I figure a 100% expansion space should be just about right for now.
I made the top out of two sheets of 1/2" oak ply. The sides are connected by strips of more 1/2" oak ply, and the sides are faced by 3/4" thick oak wood. I attached the strips with titebond III water proof glue, and the facing boards with titebond III and pocket hole screws.
For those playing at home, that means there is a 1/2" air space in the lid, which combined with the plywood should give me an R value of about 1.6ish assuming I can read charts correctly.
The top middle was reinforced with cross strips spaced around the tower hole, along with connecting strips at the front and back of the hole.
The hole itself is 2-1/8, and centered lengthwise and 1/3 from the back on width.
I finished the heck out of the inside with poly before putting on the bottom with lots more titebond and lots of brads.
I start sanding tonight, following by staining and at least a week of applying valspar. Then 1/2" ID copper on the beer lines, and running bolt holes for the tower, and silconing the heck out of the hole and under the tower rim.
The chest freezer was calked at all seams with a heavy coat, and I have dropped damp rid in.
So, what did I do wrong? This is the perfect time to speak up, since I can't change too much now...
Let others learn from my mistakes.

2011-2012