is the train ride from fussen to bacharach scenic?

If you just plan to look at the castles from the outside, I'd skip it and go with option 2. By all means switch flight into Frankfurt. No point taking an extra train trip half way across Germany.

It depends on what you call "scenic", but I don't think I would call the fastest route from Füssen to Bacharach scenic. Either end (Füssen and Bacharach) are somewhat scenic, but unless you went, for instance, down to Lindau, along Bodensee to Singen, then up to Offenburg on the Black Forest railway (Schwarzwaldbahn), I wouldn't call the trip scenic. But that's my opinion.

Adding on to what Lee wrote, the route in between offers decent scenery, although nothing too spectacular. You would have to transfer through Augsburg, and move through Ulm, Stuttgart, Mannheim, Worms and Bingen. From Füssen to Augsburg, the best scenery is in the opposite direction of travel. The Bavarian and Swabian countrysides are at least pleasant. Ulm has one of the tallest church spires in the world, otherwise, you won't see much of interest from the train. I've never riden between Ulm and Stuttgart, but I know the road route, which is rather scenic but afflicted by horrible traffic. Stuttgart to Mannheim runs mostly through cuts in the mountains and hills until you reach the broad upper Rhine valley, and you can't see much of interest. Mannheim to Bingen crosses the river, then runs through some open wine country via Worms (not the most attractive city in Germany, despite it's very long history). And as Lee noted, the Mittelrhein is very scenic.

But I agree with the others, option 2 makes a lot more sense.

Or, if you continue to fly in to Munich, skip the Rhein gorge altogether and go from Füssen to Berchtesgaden. It's in the direction of Budapest and more scenic than either Füssen or Bacharach (although the route, Füssen to Munich to Freilassing, is not very scenic.

Kara,

Of the options presented, Option 2 would be my suggestion. If you fly into Frankfurt, it's an easy trip from there to Bacharach (as short as 58 minutes, depending on which train you use). There are two rail stations right at the airport, a Fernbahnhof and a Regionalbahnhof (the train to Bacharach will likely depart from the Regional station). Bacharach would be a very pleasant location to get over jet lag!

Rather than waste time on a long rail trip from Füssen, spend the time exploring the Rhine area or perhaps take a day trip to the Mosel and have a look at Burg Eltz.

Thanks everyone - we decided to skip Fussen and were able to switch our flight (and it was a cheaper flight )!