For a daily smoker substitution is going to be your best bet. I doubt 2 weeks would be enough time to get clean. Even though I do have a neice about your size that can be clean in 24 hours.lol She's got to cheat.
They will not observe you unless they have reasonable suspicion that they think you're cheating.
None of the detox drinks work. They just rely on dillution to pass the test. You can do that yourself.
I prefer subbing with synthetic urine because I get randommed all the time and I can keep the synthetic with me at all times.