Hello!
We are traveling from Amsterdam into Frankfurt by train. We are interested in seeing the Rhine River area (2 days) and then heading to Freiburg (4 days) and finishing in Munich (4 days). I've read reviews of Bacharach, Oberwesel & St. Goar and interested in staying in Auf Schonburg castle in Rhine area. Considered using the trains but also looking at renting a car in Frankfurt for the duration of the trip. I'm not sure of the ease of driving in Germany but would like to venture out into the small towns. We are a family of 5 (teenage boys 15, 13 and daughter 11). Trying to figure out the best route to see Bavaria for the first time. We are interested in seeing Dashau and a side trip to Salzburg for salt mines & sound of music tour. Any recommendations for this trip are appreciated whether it's small towns to visit along the path, castles (there are sooo many!!), restaurants or hotels-- much appreciated!
I'm not sure of the ease of driving in Germany but would like to venture out into the small towns.
Traffic jams aren't always predictable in any given place. Trains tend to be much more predictable in terms of schedules, costs, etc. Do you think your kids would prefer a rear car seat, or riding the trains? If you are thinking that small towns lack train service, it's not so. Just look at the places you've mentioned; Oberwesel, Bacharach and St. Goar are all lined up within a few minutes of each other on Germany's most scenic train route. Boppard, the small town just north of St. Goar and on the same railway, is very worthwhile as well... and if you use Boppard as your base, most of your outings to nearby destinations (including St. Goar and Oberwesel) will be free of charge... and simple to reach by train.
https://burg-eltz.de/en/ (plus a connecting bus ride)
https://www.marksburg.de/en/circuit/
Rüdesheim
Cochem
Remagen (WW II Bridge-museum)
Here's a map of the free travel zone that is accessible with Boppard's VRM Guest Ticket, which is available from all hotels, B&B's and apartments.
Boppard itself has lots to offer, including a handsome old town zone, a chairlift to the clifftop lookout above town, a developed waterfront with hotels and a large selection of restaurants:
https://live.staticflickr.com/417/19612375184_9f51b9a54e_b.jpg
http://schnuggel-elsje.de/upload/Bilder/IMG_0131.JPG
https://www.boppard-tourismus.de/en/leisure-activities/chair-lift/
https://www.deutschlandgourmet.info/bilder/gross/5710-Restaurant-Weinhaus-Heilig-Grab-Boppard.jpg
Because you are focused on Bavaria - or at least on Munich - and on Salzburg, I think a trip to Freiburg and the Black Forest cheats you out of the time you will need in these other places and represents a major detour in the first place. I would drop it. Note that any side trips you might make once you're in Bavaria - places like Regensburg, Garmisch-Partenkirchen, Mittenwald for example - are possible by train at very low prices for a family of 5 like yours with day passes like the Bavaria Ticket (Bayern Ticket.) There is no pre-purchase needed when you use these passes - just buy them at the station and go:
Do your 3 kids want to sit for long periods of time in the back seat of a car and will there be room in the trunk for luggage for 5 people? Did you know that gasoline is around 9-10$ a gallon here?
Trains are the best and easiest for a family of 5.