So the first thing we needed to do was to pry the molding off and remove the doors, so I could cut off the left side. We used a small pry bar to pry the off the molding and pull the nails. Take your time and you can salvage most the lumber for the project.
We ended up with more than enough wood for the shelving. I also have a bunch of reclaimed cypress which we used for the shelf trim, the shelf legs and supports for the shelves.
For the trim I made it about 1/4 in wide to leave a lip around the shelves. This would give the rats a little railing and hopefully keep them from falling off. There are two sets of legs that support the four selves and I added a couple of supports on the inside wall to support the wings on the u shaped shelves.
Since this was no longer a fine piece of furniture, we just used the nail gun to attach the trim, then finished the wood with a satin polyurethane finish.
We made the doors out of cypress and used simple lap joints on the doors.
And the finished product, just add a couple of your favorite rats.