Your story sounds so familiar. My Mother is a chain smoker as well and I went out of town for a seminar (leaving my dog with her) and when I returned, my dog smells like smoke. I also did not smoke inside the house. Actually, I HATED the smell of it but just couldn't seem to kick the habit. I walk into her house only to smell like an ashtray when exiting. This should be a FINE reminder that you no longer want to smell like that.
My suggestion about possible weight gain, do something to raise your heart rate in the morning time. An extra workout per day will definitely combat any weight gain. I did not experience any weight gain although, I am extremely active. Most literature suggests 5 to 10 lbs within a year...if you can maintain your weight for a year, you should be ok.
Also, I am not sure if you were a menthol smoker, but I was and brushing my teeth a few extra times a day and inhaling after I was done helped me get over that minty taste in my mouth that menthol cigarettes felt like...
I hope this helps too. I am fascinated by the fact that I quit. I smoked from age 9 until 32...thats way too long but I am so glad that I quit.
Best of luck,