Looks amazing! I love your work. Nice clean look, and the finish is really great.
Keeping the wood from drying out is going to be really hard to do, especially if you hot smoke in it. Bob's idea of mineral oil is a good one, but it will probably take a lot, and often. Wood does crazy stuff as it takes on and loses water. Being filled with liquid and now being exposed to hot dry air is a huge swing in humidity and moisture content for the wood. This may be a hard hurdle to overcome. Only cold smoking in it could help, but I think it's still going to dry out and contract. Harbor Freight sells an el Cheapo moisture tester for wood. It can help you keep an eye on it. Maybe you leave a humidifier running inside it between cooks?
YOU WANNA THROWDOWN?
You should! Fun and fabulous prizes await you!*
I have a bunch of stuff that cooks meat outside using some form of combustion.
*Actual prizes may not be fabulous. It all depends on what your definition of fabulous is. You're not going to win a car or anything, so don't get your hopes up. Just trying to give you realistic expectations.