I have a standard issue box fan in the window, exhausting to outside.
I cut a piece of cardboard and taped it to the fan, covering the inside, with a hole just a few inches smaller than the fan blade diameter to create more positive one way flow and prevent excess exchange with the warmer/colder air outside.
I fitted a board beside the fan to fill in the gap. A folded hand towel is laid across the top of the fan and positioned to seal the edge by the glass.
Another old towel is rolled and placed at the bottom of the door to lessen the pull of air from other parts of the house.
I keep a shot glass with a flared out top on my desk. I dump pipe ash into it. A match book lays flat on top to contain odor. When it fills, I empty it into a ziplock baggie kept in the trash can. I smoke 1-3 bowls per evening.
No ash or dottle is ever left exposed to the room air. The ceiling fan stays on and the closet door stays closed. The box fan is left running for at least 15 minutes after the last smoke. Then, I close up for the night.
This is the room where we also do most evening TV viewing and my very nonsmoking wife seems comfortable.
I work from 5am until about 1 or 2pm. I only smoke in there from about 3pm until 9pm, maybe midnight on my "weekend" nights.
In the morning, after the room has been closed all night, there is a light smoking aroma but never as bad as entering the home of a cigarette smoker or the tobacconist shop. It's not apparent anywhere else in the house.
I'm coming up on a year of pipe smoking and this arrangement has been a suitable compromise for our household.