Mary Ann, I've got one. Spotted it on clearance at walmart back in February and started doing research. I feel the Okie Joe smokers are diamonds in the rough. For around 1/2 or 1/3 the price of a custom built smoker (mine was ~$150) you're getting a great starting point. A little bit of time, money, sweat and perhaps a little blood, and this smoker can be as good as any of the super over priced custom smokers.
Lots of good info in this thread:
http://www.smokingmeatforums.com/t/127173/temperature-control-for-my-oklahoma-joe-longhorn/60
Buy some red RTV from
Amazon (I got #81160) and seal up the 2 halves of the FB (fire box) and the FB to CC (cook chamber) areas as you build it.
My posts are near the end. There's a picture of my charcoal box, just 24"x24" piece of expanded steel folded and cut. Purpose (to me) is so I can pour in a LOT of charcoal without worrying about any rolling out of the vent.
Also a picture of my exhaust re-locator. Most use a 4" (or is it 3"?) piece of vent tube to bring the exhaust down to grate level. Purpose here is that with the exhaust opening on the top your smoker doesn't trap the heat at all. Heat from the FB enters the CC and rises to the top where it's drawn toward the exit and then exits. It will still work without forcing the exhaust down, but the smoker will work better with something forcing the exhaust down near the cooking grate. Think about a hot air balloon. They are open on the bottom so the balloon fills with hot air, Some heat pours out the opening at the bottom, but if they had an opening on the top no heat would ever be trapped in the balloon.
I have tinkered with a thermal barrier between the CC and FB, but mine failed so I've been cooking without one.
Others have sealed the door mating surfaces with different material, I've not done mine yet.