Which Firefly character do you find hardest to write? I find myself struggling with River. Especially in post-BDM fic because I want to show that some progress has been made in terms of her mental health, but I don't think it's appropriate to show her as being fully healed either. And in pre-BDM fic, I find it sometimes hard to capture the 'she's-crazy-but-she-kinda-makes-sense' vibe that the show's writers did so well.
River is easy for me, though I moestly write post BDM. Wash and Inara are the two I have to almost pull teeth to write--hence I usually chicken out and stick to what I'm comfortable with *g*.I agree with you on River pre-BDM, though. There's almost too much trauma there to deal with.
Wash and Zoe. Wash has such a particular way of phrasing and choosing his words. It's hard to predict, let along copy. And Zoe is, just like said above, more about the "how" than the "what" and it's a challenge to describe it just right. And, incidentally, Kaylee. The mix of sweetness with an occasional wickedly worldly twist.The other characters just tend to tell me what they want to say and how, but with these three, it's a case of actually working it out. Hence my general lack of writing about them, hehe.
I honestly don't find any of them hard to write. Some are harder for me to think of good stories for, but I enjoy working with all of them. The only main character who hasn't gotten much play in my fanfic is Book. I think I've maybe given him a line or two, total. Whoops.
River is the hardest for me. It's very difficult to get the tone of her voice right. She doesn't use big words, but what she says is often very convoluted and hard to follow, but when you get the trail it sorta makes sense.