Personally I don't think it's narrow, however for the most part there is very little run off before the armco, and I'm talking 10-20ft. I've done far more bike laps than car laps round there but don't any longer ride at any real pace round there due to the difficulty in spotting fluid spills. Shame really, because I much prefer it on the bike, but sadly as the place got busier the spills got more.
As I've said before though, it really isn't anywhere near as bad as some of the drama queens make it out to be, it's just a road, half ounce of common and a bit of ability and all will be well. You can of course get caught up in someone elses crash, but that can happen anywhere.
Remembering the track? I tended to remember the difficult corners early on, but at a guess I reckon 50 ish laps before being fully confident of the whole layout.