I went to the ring last year and in 3 weeks time am making my 2nd trip. I think that on the continent there are certain items you have to have in your car-ie, u must have a spare bulb kit, first aid kit, fire extinguisher, hi-viz vest and must carry all documents at all times, oh and a GB sticker. As for the headlights-i just stuck those deflectors on-i dont think they did anything because as you say, the coop's headlights are very awkward, but if they are stuck on then at least you have made the effort!
Be careful on the ferry-i caught my front spoiler on the ramps and also had to do 3 point turns to get around the corners on the boat.
Last year we stayed in a town called Cochem, but to find our hotels we jus went on the interweb and searched in a 30 mile perimeter around the ring, you can actually find some very nice and cheap digs!
I highly recommend you go.
Matt