The service manual can be found here. I suspected the centrifugal switch because I read on some other forums about the motor being stuck "open" or "closed". The behavior to me said "stuck open" so I replaced the motor thinking this was the most obvious issue. At least Im now prepared with a second motor for whenever the motor does give. Also had some good practice taking the dryer apart, and putting it back together.
Very simple to do, trickiest part was putting the belt back on the drum, motor and tensioner pulley.
And yes, the drum does stop when you open the door (even when the dryer is "off"), but resumed immediately upon the door being closed again.