Gear for Photographing naked-eye comets

Greetings!

What would be a good setup for photographing a comet?  The recent reports of C/2012 S1 could be good news (or, of course, could be the next Comet Kohoutek).

Equipment-wise, I have a Nikon D90 (crop-sensor), 35mm f/1.8, 50mm f/1.8, and an 18-105 zoom.  I imagine I can get good results with something I have, and maybe need a tripod and or clock drive or something.  Or do I need something longer than 50mm? Would this be a good excuse to get a tele-zoom like a 70-300 f/4-5.6?  Or would that be too slow and I really need a telescope and adapter?

I found some articles on the web that differ in terms of equipment recommendations.  I totally get that we're guessing on whether this comet would be naked-eye-visible at all, never mind how big, bright, etc.

Technique-wise, some  articles seem to recommend trial-and-error with exposure times.  Another is focused on film techniques and also is general in terms of what kind of comets.

If I have to save pennies and learn new gear, I'm happy to get started.  Thanks in advance!