Once you enroll Tpapn will give you a whole packet of instructions, including a list of "acceptable" doctors, (addiction specialist) to do an evaluation on you. I tried to go to someone else and they denied me but I know some people have been able to. On the list you'll generally find that they all cost around $300-350. The evaluation will result in a recommendation, in-patient therapy or outpatient (IOP, intensive outpatient therapy). Most of the outpatient programs were I think like 6-8 weeks, three times a week. Idk how long the inpatient would be. Depends on each person's evaluation results I guess. I did outpatient. I was able to search the Internet and find an outpatient (IOP) much much closer to my home than the one my assessor recommended, and my insurance actually paid for it! Usually at the end of the 8 weeks, they try to get you to keep coming for "after care", more money and more time! I was able to avoid that. At the same time as your IOP, you are also required to do 90/90. That's attend 90 AA or NA meetings in 90 days. They are an hour long and you can find any meeting near your home to attend.
You will not be able to work until you get approval from your IOP counselor. Usually near the end of your IOP term, say around 6 weeks. And before you ever start the IOP it will probably take a couple weeks to get the eval scheduled and then find an IOP that you can attend. Also, working during your 90/90 would be difficult, not impossible but I know I wouldn't want to work 12 hours then have to go to an hour AA mtg before going home!
So, all in all, I think the soonest you can expect to go back to work would be about 2-3 months after enrollment.
Hope that all makes sense.