I have tried smoke in cabin both in the sim and real life. The real life one was called to us by the stewardess as we were passing about 1000' and we declared the emergency, took the radar vectors and landed back 7 minutes later. Would have been sooner if it had been VMC. There wasn't time for any emergency checklist.
We had the full works in the sim with the smoke machine on. One guy on the emergency checklist only and one flying single pilot. It remains that way until completion of the checklist or start of final approach.