We found the perfect lake house after looking for a long time. A super smoker had built it in the 60's and, believe me, we almost walked, but got it for a great price so wanted to give it a go.
We stopped on our way to the closing and got 15 gallons of oil based kilz. Left there & started cleaning walls & painting. We left the green shag carpet in as a drop cloth & started rolling. I'll have to ask Mr. Schwack how many coats of paint we did - I've tried to forget.
Then we stripped everything out - cabinets, carpet & tile. The walls were wood paneling that we kept at the time since it was just a lake house but we had so many coats on it that the smell was basically encased. Slab house so we put down 6 mil plastic and new flooring. Oddly, the metal window screens stunk so we had to deal with that, too. Luckily, there was no central HVAC, so we ditched the window units & put in a new, clean system.
I am very sensitive to smells - the canary in the coal mine - and it's been years and I still didn't smell it. That said, we just finished a full renovation where we gutted it, completely re-sheetrocked, new flooring, etc. We retired here & everything we've put into it over the years has been worth it because we knew it was the right house for us. It was a lot of work, but we've never regretted it
Per Mr. Schwack: 2 coats of oil based kilz & 3 coats of latex. Key was letting each dry completely between coats. He said you might check into some of the shellac based primers that are used in fire restoration if it's really bad.