Many ED Bimmerfest members photograph their car in front of Neuschwanstein. Here are the directions to the photo spot - so you can spend your time touring the castles instead of boring your wife or significant other looking for the perfect photo spot.
Basically, driving down the main road, you will see some open farm fields off to the right. There is a "no traffic allowed" sign at the entrance to the street (Red circle with white center), but if you don't drive too far no one seems to mind. Park near the tree at the fork in the road (three hundred meters from the main road) and photograph your car with the castle in the background.
Late afternoon is probably the best time for a shot. A polarizer filter is a good idea to bring the colors out in your paint job. Try to a long lens to help magnify the castle, or less of a telephoto of you want to emphasize the car.
Here are directions from the parking lot to the photo spot: