1) The nice thing about Harris is that there are two tracks in the statistics and in the microeconomics sequence, a "regular" version and a "advanced" version. The regular version does use some calculus, but I think the material is still very accessible. The advanced versions will use quite a bit of calculus and will be challenging. Math camp will be a good refresher and there are algebra and calculus courses in the fall for people who need more background. I do think that learning the micro and stats, while sometimes painful, is important for someone who wants to do policy work, even someone interested in communications and management.
2) The first two quarters are very structured, as you will probably have no choice in your classes. However, after that you will have 11 classes to elect entirely on your own. While having a lot of abstract material up front was sometimes frustrating, I do think there is sufficient time for electives. The quarter system gives you a lot of opportunities to take a range of classes, which people at Harris use to take classes across the university (at the business school, the law school, the econ department, foreign languages, etc.)
3) A lot of students do internships in DC and for the last several years there has been a winter quarter DC networking trip to facilitate this and job hunting. Students this year met with Harris alums in positions around DC (IMF, World Bank, etc.) and also used the trip to arrange their own interviews on the side. I did not go, but I heard from those who did that it was a really valuable experience.