Twistr==wow, sounds like you have made great progress. I forgot to mention that when I trained Rockie to sit at the garage door I too had the door open but unlike you, I was too afraid to walk away and trust him not to run out. I don't really have the issue of the front door because we never go out that way--I do have a huge issue of him going ballistic if anyone (especially dogs) pass by on the sidewalk (I've even tried spraying him with a water bottle as someone suggested but that only got me a very wet and still barking pooch--LOL).
Breezeway--I also like your idea about the leash--I'm going to try that as well. Lately we haven't had as much trouble getting him back when he runs out (when the kids let him out) as we've had a ton of snow dumped here in Colorado and I think he figures it's too cold out for his little toes so he runs back in and gets rewarded at the same time.