I agree with Tom about pork. If you want an absolute slam dunk the first time you use your cookshack, smoke a pork butt. It is virtually impossible to not make a great pork butt in a cookshack, that is as long as you don't over smoke it.
If you are looking for down the road, some of the more adventurous, or interesting things I have tried is pastrami and buckboard bacon, both which were absolutely incredible and I would highly recommend. Do some searches and you will find some great recipes on this forum. Some things that I have not done, but plan on trying, are ham, jerky, and cheese. Enjoy your new cookshack. Tell us how the first smoke goes.