I'm with Bob on this one. A remote thermometer is the best way to go for big chunks of meat done low and slow. Just don't use them at higher temps as they'll burn out (from someone who's done just that). If you want to spend a little extra cash, the wireless models are nice. There are a couple of different brands out there and a few of them have two probes. That makes it nice for monitoring both the meat temp and the grill temp.