Losing a bunch of weight and quitting smoking at the same time is totally doable. I did it at age 42. Cold turkey on the smoking and alcohol, plenty of water, low sodium, lots of vegetables, low fat, low carb (low glycemic carbs only!). I would advise against serious weight training, as the muscle gain I had was completely regrettable. Do lots of cardio instead, start with walking 30 mins per day and slowly boost it to 90 mins and more intense walks. I personally can't run much due to a bad knee, but walking is great.
You will love the new you.