(Updated 10/20 with additional pictures.)
Kudos go out to LoadmasterC141 for winning the "Where Is Sam Now" challenge, and all the other readers who figured out individual clues. If you didn't catch my comment in the last thread, I am currently in Bacharach Germany, on the Rhein River between Bingen and Koblenz. Loadmaster even figured out the building before I posted my next clue, which was going to be a picture of it. So here it is: Burg Stahleck, a 12th century castle-cum-youth hostel.
This stretch of the Rhein has more castles than they know what to do with. Most of them were originally erected to enforce the various tolls the local barons imposed on commercial river traffic. Many of them changed hands several times during the 30 Year War, were occasionally occupied by the French during their regular incursions into the Rheinland, and all were sacked and many destroyed by Napolean and the Revolutionary French Army when they came through the area. Burg Stahleck was taken by the pre-Napoleanic French Army during their occupation of the Rhine's west bank in the 1680s. They destroyed most of the fortifications, the keep, and part of the longhouse; the ruins sat for 350 years before restoration began in 1926. It wasn't completed until 1967, but what resulted has to be one of Germany's neatest Jugendherbergen. It's actually pretty modern inside, which is a little dissapointing, but you can't beat the views.
Burg Stahleck sits several hundred feet above the sleepy town of Bacharach. The region is known for its Riesling wines, and indeed every acre on sunny south-facing inclines seems to be cultivated. The town still has its original Rathouse (1368) and Post (1724 - surprisingly still bearing the Nazi Eagle painted on in 1936). The church (Sankt Peterskircke) is dominated by the few remaining walls of a beautiful chapel above it. Tourism seems to be the mainstay, although it's heavily dominated by German nationals. I've heard only a handful of English speakers, although it is of course the shoulder season. Unsurprisingly, weinstubes take the place of bierstubes here. Wednesday night some friends and I went to one and enjoyed a sampler of the local Rieslings (plus a Rotwein thrown in for good measure). This is still Germany though, so I made sure to enjoy a local Weissbier.
Thursday I took a boat down the Rhine to St. Goar, just past the famed Loreley, to explore the Rheinfels Castle. Reinfels was once the mightiest fortress on the Rhine and was considered invincible. Indeed, it was continually updated with the newest defenses after the first portion was built in the 12th century, and they were never breached. The castle was surrendered without a fight to the French Revolutionary Army in 1797. They promptly ensured they'd never have to seige it again by blowing up the fortifications and later the main castle as well. Most of the fortifications' stones were used to fortify other castles, so what remains is only a fifth of the 18th century size. It's still massive; I spent three hours exploring the ruins and could've spent more if I'd fully explored the underground fortifications and tunnels. The neatest thing is that very little of the castle is restricted from the public - you're generally free to poke around at will, and that includes squeezing through tight underground passages. You can imagine mail-clad defenders scrunched down in the galleries, crossbows at the ready, nervously peering through the arrow slits, waiting the next onslaught of beseigers.
So, that was my mini-trip to the Rhein. I'd like to go back with my wife someday and spend more time, it's very beautiful and relaxing. If anyone is interested in staying at Burg Stahleck, you can find more information here (in German), also older information in English here.