Hi Jack,
I did make it to Neuschwanstein, however, I did not get the shot I wanted. I settled for the side view from Marienbrucke. The face of the mountain was extremely steep and I did not want to risk the walk down. Based on Google Earth pictures, I think it is possible to get somewhat of a front shot from the European Trail (but more of a side shot). However, I am convinced that the popular front shot in postcards is done by helicopter or a professional climber (even this is questionable).
If you want to make a hike of it (and a steep one) look at the following on Google Earth and see what you think:
Take the shuttle to Marienbrucke. Then cross the bridge which I believe is this European trail 4 I have found on other websites. This will go along the ridge of the mountain. This is a steep hike and will really need to be dedicated to hiking if you want to do this. I think the problem will be trying to get down the face for the front shot. I think it is too steep and not possible.
Sorry this isn't more help or encouraging, but again, I think the shot is with a helicopter.
Good luck!
Andy
PS - I think the paid tour of the castle is a total rip off! Knowing it, I wouldn't have done it. Seeing the outside is a million times better than the inside, but who knows, others may love it.