I am on one month with the princess. I am burning lodge pole pine and get 12+ hour burn time when the temp is above 20. Below 20, I have very little coals left to get the fire started again, but it starts. Drafty weird house stays above 70 when it is above 20 outside, but dips to 67 when it is below 20. My only complaint is the smoke that comes back into the house when loading. Will attempt to fix this next year with a new flexible pipe down the chimney. Sure wish there was hardwood in this valley!!
If you have smoke coming back into the house, you have too much unburned fuel left in the firebox. Our King will do the same thing especially since we have it hooked to 6" pipe. My suggestion:
1. Try to load your stove on a schedule that leaves as little unburned wood in the firebox as possible, but yet has enough hot coals that it will start your new load.
2. Or, if you have too much unburned wood in the firebox, try turning your thermostat all the way down for 1/2 to 1 hour before you load. This may "cool" what's left in the firebox enough to allow you to load it before it starts smoking again. Obviously, you still want enough hot coals to start your new load. And keep in mind, turning the thermostat all the way down still allows some air into the firebox.
I know #2 sounds odd since it goes against traditional thinking: Open the bypass and heat the flue, creating more draft. It's worth a try and just might work for you. The biggest thing that will cause smoke spillage is unburned wood left in the firebox during loading. We burn mostly Lodgepole also and have adjusted the way we load, to the point that we have very little problem with smoke spillage. You just have to play around with it and see what helps.
EDIT: If these suggestions don't work, try opening the bypass and turn the thermostat up on high for about 15 minutes, heating everything up before you open the door.