Rudesheim boat tour. Help

Burg Rheinfels in St. Goar is a huge ruined castle. my favorite in the area. Best to stay on the boat all the way to St. Goar or Boppard and then use the train on the way back to visit various villages such as Oberwesel and Bacharach.

How long should the trip take to st Goar and to tour the castle?

The cruise takes 1.5 hours. Rheinfels is good for an hour or so. Ditto what Stephen said about the cruise. See the towns south of St. Goar by train - Oberwesel is only 5 minutes from St. Goar and Bacharach only 10. BUT... you'll need to take the train to Bingen and ferry across (ferry runs all day long) from there to R'heim (if you're going back there, which isn't completely clear from your post) as the train doesn't cross the river (by the way, no "c" in Rüdesheim, and it's not a "sh" sound - it's an "s" sound and then an "h" sound.)

If you want a tour of a genuine, never-destroyed Rhine Castle, Marksburg Castle should be on your list. You can cruise to St. Goar - maybe with a 1- or 2-hour stop in Bacharach or Oberwsel - then see Rheinfels and/or the town - then FERRY across (runs all day long here too) the river to St. Goarshausen (that's the side where Rüdesheim is) and take the train north about 22 minutes to Braubach and Marksburg ("virtually unchanged from Medieval Times.")

Braubach scene
Braubach scene
Marksburg
Marksburg info.

After Braubach catch a direct train to Rüdesheim (45 min.) or wherever.

The RHEINLAND-PFALZ TICKET will cover all your train travel and the St. Goar ferry crossing.

"taking a boat ride up to St Goar"

From Rüdesheim to St. Goar is up on the map, but it's down the river, with the fairly fast current. I would take the boat to St. Goar, then the train back to Rüdesheim (if that's where you are going). The boat goes very slowly up the river, from St. Goar.

I spent a lot more than an hour at Rheinfels castle. Even as a ruins, it's extensive and interesting. I'm not sure I would have time for the boat ride and Rheinfels and Marksburg in a day, but everyone is different.

"I'm not sure I would have time for the boat ride and Rheinfels and Marksburg in a day, but everyone is different."

It would indeed be a long day - but then the days are long at this time of year. Marksburg closes at 5 pm so you would probably want to be on the first boat from R'heim in the morning, and you'd want to plan out your day thoughtfully using the DB train schedules. Alternatively, see Marksburg on a different day.

"I would take the boat to St. Goar, then the train back to Rüdesheim (if that's where you are going)."

Just want to re-emphasize that you need a FERRY crossing in St. Goar or in Bingen, in addition to the train, to get back to Rüdesheim, which is on the opposite riverbank.

Lot's of good info so far, but one additional bit that I would add is that if you decide to go to Marksburg (fantastic place by the way, inside and out) unless you are fluent in German you might want to check out what time the English language tour starts. Last year in mid-May the English language tour started at 1pm - and that determined the timing of the K-D cruise we took to get to Braubach - also it took us close to 30 minutes to get from the boat dock up the 'hill' to the castle.

Just to add a bit of important information. The ship and Burg Rheinfels only take cash, no credit cards.
Show your train ticket to get 20% off on your boat ticket.

Great information, thank you for all the advice!