Couple of my mates have been on their Dukes, no problems from what I gather, although they did say the roads aren't too great, and the fuel can be a bit hit and miss, as for parking/leaving your bike etc, on race day there's plenty of parking outside run by the locals, basically pay them peanuts to look at your bike in admiration all day from what I gather.
Might seem a bit scary, but they've been back twice now, so must be OK.