You're welcome. Don't worry about sounding "retarded" haha, you don't. I live fairly close to CC and know a few people who've been there as students/faculty, so I personally don't mind questions. That's what we're here for, right?
About word limit: I don't see one specified on the online Common App, so I'm going to assume there isn't one. Don't be excessive, though. But with consideration to the readers, try to only keep it as long as (if not shorter than) your main common app essay.
About talking to a CC rep: Just call the admissions office. Contact info can be found on the school's web site.
As for writing style (narrative vs. list sort of format), I would think that either works if it reads well. CC seems to be into creative thinkers, so narrative might work better, as long as you can get your point across.
Seminars: As in seminar-style classes? Basically they're just big discussions. I sat in on one seminar class. They had read this book prior to the class, and the just kinda...talked about it...and how it related to gender issues (because that's what the class was on). Prof posed one question, or a student might make a comment, and then another student would respond/add to that. It was like the conversation at a dinner party with intellectuals...without the dinner. haha
Field trips: Basically field trips are just an opportunity to go to a place outside of the classroom and learn about that subject. Like at CC, some of the geology classes go to rock formations or rivers and study them. In middle school, we went to the office for the major local newspaper, and we got to ask some of the columnists questions, tour the grounds, see how the paper gets printed, etc. So as an econ major (or really, the answer for your supplement doesn't need to have anything to do with your major), what's someplace you would want to just tour and visit? Who would you want to interview?
textversion: Really, just think about the things you're passionate about. You don't have to map out the syllabus for some super-intellectual, intense subject. What extracurriculars are you involved in? What's your intended major? What books do you like to read? Pick a subject matter that interests you, however silly or obscure, and start free-writing some ideas.
Hope that helps.
Honestly, don't have mine quite done yet, but I'll be happy to post or PM to you guys if I finish it reasonably before the deadline. :-)
Best of hopes!