My first UDS. I decided to do gas instead of charcoal, so a 4" burner is inside a 12" pan recessed on the bottom (why it has legs). I've seen some good ideas here, so I'll just say it's not quite finished.
Mine is a $6.99 candy thermometer from the local hardware store. It didn't have threads on the back so I mounted it just above a short stainless bolt and secured it inside the drum with a stainless hose clamp.