Why and when to visit
Because you like road trips. September is a very good option weather-wise and also can fit quite well if you want to visit October fest in Munich.
Getting there and around
You can get a flight to Berlin and return from Munich. Drive the in-between and make sure you stick to the romantic road. For this double-check your navigation settings and select to avoid highways and toll roads.
Get ready to have a lot of meat, sausages, potatoes and cabbage. Whatsoever it is delicious.
Try to book in advance the accommodation in the places you want to stay overnight, as it might get busy and you end up paying more than you would like.
Castles, castles and more castles… It does not matter what you have seen in Disneyland, the real ones are far more magnificent, and does worth visiting. Countryside and small towns make the trip worthwhile.