I've had some memorable two week tours in the past, and some great long-weekend tours as well. Two weeks is certainly plenty of time to cover a lot of ground and see a lot of sights if you plan it right. These days, I prefer taking at least 3-4 weeks, and have been known to take some unpaid leave from work to make sure I get the time I want, and I can usually work out in advance how much of that I'm going to need (if any). I just see that as one more expense to save for prior to the tour.