From Cologne, I will take a train down to Bingen and then take a ferry to the different villages from there to Braubach. I need to return to Cologne by 11pm to catch a night train. Anybody seen a suggested itinerary that includes the best sites of the multiple villages? Thank You!
Go to the K-D Rhein schedule. You'll find that there are effectively about 5 runs a day, so you can stop at four towns. You'll have to leave Köln pretty early to get to Bingen for the 9:30 boat, so that might limit you a bit. If you take the 10:30 boat, you could spend an hour in Bacharach, then go on to St. Goar and Rheinfels for 3 hours, but that would get you to Braubach too late for a tour. You'd probably be better off to use the German Rail (Bahn) website and figure a train schedule with limited boat legs to maximize your trip. And remember, there are limited opportunities to cross the river (St. Goar/St. Goarshausen, Boppard/Filsen), which will limit what you can do by train, but the K-D boats stop on both sides. Instead of all the way to Bingen, you could go just to Bacharach, see it, take a boat to St. Goar, see it and Rheinfels, then take the train to Boppard and the boat from there to Braubach.
Have you considered making Braubach the 1st stop on your train trip from Cologne? Tour there and then continue down that side of the Rhine to Ruedesheim. Walk around there, take the chairlift up to Germania, and then take the boat up to St. Goar and/or OberWesel. Continue on that evening to Cologne. You could of course get off at Bacharach, but I wouldn't. It just is not that special of a town and you are already planning to stop at other, very similar towns.