Usually, crowns can be finished in about one week.  You would need to visit twice; once at the beginning of the week, and once at the end of the week.  During the interim time, the dental lab will be hard at work custom crafting your crowns.   More time may be needed depending on if the clinic does not have their own lab, if there are many crowns to be done, if a complicated root canal procedure is involved, how busy the lab is, etc.  It is important to schedule your appointment as far ahead as possible to ensure your treatment can be concluded during your stay.