Favorite response regarding interpretation: "Well, that might be your/their/his/her interpretation, but my Bible clearly says...."
People claim they recognize the subjectivity of the canon but rationalize the objectivity of their understanding by appealing to "God's hand" in the process of canonization. It was a "human" process, but since God must have guided it, we should be able to objectively understand "the plain facts" of scripture. I think there is such a thing as a doctrine of revelation, but that's not the same as an objective, unmediated understanding of scripture.
In short, those explanations you suggest are still met with a "Yeah, but..."
This forum is really perfect because even here I'm misunderstood! Haha.
I think my field and specific interests are sort of unique in applying what you're talking about. I don't just "study the Bible." I feel like putting it that way doesn't do it justice since Biblical Studies is an actual field--one that I do not claim. I'm interested in how people interpret the Bible. So my 30 second explanation would be just that: "I'm going to be studying how we interpret the Bible." The difference between my explanation and yours is that most non-academic people you interact with (I could be wrong about this) aren't affected by mummies on a daily, weekly, monthly, or even yearly basis. They know what mummies are because they've seen specials about King Tut on the History Channel. Hence, saying you study mummies sounds really cool! (What you're studying does sound interesting, btw.)
However, because the question of interpreting the Bible hits so close to the weekly, sometimes daily, lives of most people, my experience has been (and maybe I should have been this clear in my original post) that when I tell someone "I'm going to be studying how people interpret the Bible," that almost always prompts one of three follow up questions:
1) You interpret the Bible? I just read mine and it tells me what I need to know!
2) You mean like trying to understand what the original author meant?
3) Well...how do people interpret the Bible?
In response to any of these, I can honestly say that I try to keep it simple. But this is something people are genuinely interested in. They can tell if I'm bullshitting them in order to "not confuse them" or because I think they won't get it. And when it comes to this topic, that just pisses them off. Really though, they don't have the, as you said, specialized knowledge to understand the issue from my perspective, so when they push me for more (some do and some don't) and then don't get it they tend to get frustrated. That's what I was trying to get across in my first post.
I have a graduate degree in another field (English), so I am well versed in simple explanations. Whenever people asked me what I was studying, I would say, "Kurt Vonnegut" or "American literature" and that would basically be it. I'm definitely with you in that I want to just enjoy people for who they are. I learned long ago when and when not to get "academic."
Also the responses to Derrida are fascinating, haha. I've never studied philosophy formally; Derrida is really important (arguably) in literary criticism and has become popular in the last 20 years in biblical/theological hermeneutics as well. But certainly...it seems people either love him or think he is and always has been completely irrelevant. My interest in deconstruction was a major factor in getting accepted to Northwestern, so... still relevant in my field.