Converst Brinkman horizontal smoker to propane

I have a Brinkman off set  horizontal smoker that burns wood or charcoal and would like to convert it to propane to cut down on the baby sitting time.

Any suggestions? Works great as it is and I've had it for at least 10 years and done lots of turkeys and pork roast and three whole pigs (under 50 lbs each, not at the same time) and had great luck with all.

Thanks for your input.

Monkford