Need a little advice since we don’t have a lot of time- southern Germany, Switzerland and Austria.

What do you want to do and see?

It's very rushed to cover all the highlights in three countries in two weeks.

I'll specifically ask what you are expecting to see in the Black Forest. It is beautiful, but there are far more beautiful woodland areas in North America, if that's where you're based.
The Mosel valley downstream from Trier would probably be a better experience.

Otherwise, with 2 weeks, a quick Maastricht-Trier/Mosel valley-Luzern (rather than Bern)-Salzburg-Munich route is a bit rushed, but feasible in a pinch.

Is it Baden Baden because it is in the RS book or because one or more of the attractions there appeals to you?

I've stayed there and enjoyed it, as much for the Sofitel room we had, and it a quiet place like we like. You might prefer Gengenbach for a Black Forest experience, but as upthread, what sort of Black Forest experience do you want?

I was just listening to a wonderful performance of Beethoven's Sixth by the Berliner Philharmoniker at the Festspielhaus in Baden Baden recorded in 2015 (Bernard Haitink conducting). Lovely.

I find it hard to think of an 11 year old having a great time for 2 days in Baden Baden. What did you plan for him?

You aren't too far from Rust, but that's completely different.

"We have never been to anywhere in southern Germany, Switzerland or Austria."

Welcome to the forum! Couple questions, couple comments...

Maastricht is a lovely town. How many of those 13-14 nights will you spend there?

And is it your plan to carry out this trip by car or by train?

"...want to make our way to the Black Forest (thinking maybe Trier then Staufen- approximately 2 days) then to Bern for a day or two... "

By train, Maastricht > Trier > Staufen alone will require 11 hours or thereabouts on multiple trains. Were you planning to make this journey in one day, or spend one night in each place? That seems super-rushed, no matter your mode of travel. If you forget the Trier stopover, the train trip to Staufen takes closer to 6.5 hours. Bern isn't too much further. OTOH, I'm not convinced that Staufen and Bern, for your very short time, are worth the trouble and the expense if you intend to end up in Munich and Salzburg later. There are all kinds of great places on a tighter trajectory between Maastricht and Munich/Salzburg, and I'm tempted to send you to some of those places... But if Switzerland is really important on this trip, maybe something can be worked into your itinerary (something superior to just Bern, I hope.)

It does sound like you might be modifying Rick Steves' quite rushed bus tour itinerary for Germany - Austria - Switzerland. I think there are good reasons to leave that itinerary out of the equation and to just plan something that suits you and that also avoids extra ground travel that doesn't really pay off. As others have said, 3 countries might be one too many anyway, and more details about your interests will elicit better tips from us.

Oh my goodness, thank you so much for the speedy response’s everyone. It sounds like I’m trying to bite off more than I can chew in that time period. I really appreciate all of you sharing your knowledge and advice.

Here are a few more details if anyone has some suggestions for us of where we should go.
My parents and my 11-year-old son are going with us. My mom‘s family is originally from the Black forest region, more specifically Langenbach, and she would like to go through that area to see it since we’ve never been and we’re not connected to any family there currently. We are really open to any neat places, but with our son along for this trip, I’m not sure he would like all of the adult things from Rick Steves travel guides.
We plan on only staying in Maastricht for about a day and a half, then heading out to explore via train or plane preferably since I’m a little nervous driving when I’m unfamiliar with the area. We are trying to get a historical and cultural taste of the surrounding areas.
Thank you again for your time and help! Sincerely,
Kendra

I've been thru the Black Forest. it's pretty, but we just prefer to spend our time in The Alps.

We prefer to spend a long weekend in Munich, rent a car and head south into the Austrian Alps--doing day trips out of Innsbruck. From there, we like the Grossglockner High Alpine Highway south of Zell-am-See ending in Northern Italy. We can hop on the autobahn for an easy ride back into Innsbruck. It's also easy to get up to Salzburg from this region.

We do not travel into Switzerland because Tirol has incredible mountain scenery, it's cheaper to travel in, and it's easier to travel in than Switzerland--2 hrs. to the west. They also have an incredible number of bed and breakfasts to stay in.

"We are trying to get a historical and cultural taste of the surrounding areas..."

OK, so with the family connection it sounds like the Black Forest is "on." I had to search out Langenbach. It's a village/neighborhood of about 300 that is now part of Vöhrenbach.

There are different ways of getting there that don't involve a train since neither Langenbach nor Vöhrenbach has a station.
I would suggest using Bus 850 from Donaueschingen (the rail station town where the Donau/Danube River has its source.) The ride is direct and takes about 40 minutes. Visit Langenbach on a weekday for frequent buses. Bus schedule:

https://www.v-s-b.de/wp-content/uploads/2021/11/L850_2022.pdf

This map shows the Black Forest Railway between Offenburg (on the main line from the north) and Donaueschingen. It's one of Germany's most scenic train rides. Also shown is the Hells Valley Railway between Donaueschingen and Freiburg (also scenic.)

https://upload.wikimedia.org/wikipedia/commons/thumb/4/4d/Verlaufskarte_Schwarzwaldbahn_%28Baden%29.png/518px-Verlaufskarte_Schwarzwaldbahn_%28Baden%29.png

There are numerous places you might stay. In addition to Langenbach, a big draw for those interested in local culture is the Vogtsbauernhof open-air museum in Gutach (not on map but near Hausach, and it has a rail station too.) It's great for kids, I think. And there's a summer bobsled run there too for a little excitement. So I think I'll suggest that you stay closer to that place. Gengenbach is a good choice - old world town with several good options for lodging and food. Gutach itself might work for you too. Haslach is another nice town. I stayed on a farm in Steinach (station there too) a few years ago (good if you want it quiet) and walked about 10 minutes to the station for outings. I believe Steinach is still one of those towns which offers the free KONUS card for free train + bus travel around the Black Forest. (Gengenbach is too, by the way.)

https://www.traum-ferienwohnungen.de/13558/

I booked via email with Herr Schöner, the owner/operator who lives onsite.
schoener-steinach@web.de

It's a 2-br/1 ba apt. for max 5 persons. When I was there there was also an efficiency apartment on the top floor - though it's not listed now, you might ask about it if interested. May and June look available based on the posted calendars. It's priced at less than €300 for a 5-night stay for 4 adults + 1 kid. There were just 3 of us (all adults) and it was fine for us. But I'm guessing meals for 5 would have to include a seat or two on the covered porch (which btw has a lovely view of fields, hills and orchards.)

I'll think a bit more about the rest of your trip.

I repeat my suggestion for Rust - an 11 year old would love it, especially if he had been to the model railway and outdoor museum near Hausach.

Let's say that after Maastricht you have 12 nights to distribute.

3 nights in the Black Forest

Day 1: Maastricht > Black Forest: Long trip. The best train routing (5.5 hrs. to Gengenbach.) would be Maastricht > Aachen > Cologne > Black Forest. I think your best strategy for exploring a bit of history in a brief amount of time is to break up this trip with a stopover either in Aachen or Cologne. Each city has a stunning and historically significant cathedral. Cologne has more to see/do, while charming Aachen has a bit less as well as a very attractive old-town center. You can stow bags at either station while you sightsee. I suggest you gather some info to decide which place suits your group. I could see a travel break of 3-5 hours depending on your interests. Sample schedule: Lv Maastricht 9:19 - 11:15; 11:15 - 15:55 stopover in Cologne; 15:55 -18:49 ar. Gengenbach. (Schedule would be similar for Aachen stopover.)

Day 2: Day trip by train + bus to Triberg and Langenbach
Day 3: Day trip to Vogtsbauernhof / summer bobsled and Schiltach (handsome half-timbered town)

Gengenbach is also popular as a springboard for visiting Strasbourg FR. Freiburg is also a day trip option.

Gengenbach itself has sights you might fit in here or there:
https://www.tripadvisor.com/Attractions-g1142455-Activities-a_allAttractions.true-Gengenbach_Baden_Wurttemberg.html

3 nights in Munich

Day 4: Train Gengenbach to Munich - sample schedule 10:06 - 14:27. Maybe you want to break up the trip with a visit to something in Stuttgart?? With the 10:06 departure your train would stop in Stuttgart at 12:08. What looks fun to you there? Many go there just for the Mercedes Museum. (There's a Porsche Museum as well.) If you made a 4-hour stopover there you'd still be able to get to Munich by around 18:30 or 19:00, I bet.

https://www.tripadvisor.com/Attractions-g187291-Activities-a_allAttractions.true-Stuttgart_Baden_Wurttemberg.html

Day 5 & 6 Sightseeing in Munich (there are plenty of tips elsewhere...)

2 nights in the Alps - Mittenwald (good area to visit, as David suggests.)

Day 7: Munich > Mittenwald, a direct 2-hr. train ride. Great mountain town, great scenery, great atmosphere.

Sightseeing on Days 7-8, morning of Day 9:

Day trips on public transport to Seefeld and Innsbruck (Austria,) Garmisch-Partenkirchen, Ettal, Linderhof, the Zugspitze and other places possible.

Find sightseeing tips for Mittenwald and the Zugspitze here: https://hastingshouse.typepad.com/hastings_house_us/2007/04/mittenwald_germ.html

Area public transport map:
https://www.dbregio-shop.de/uploads/files/RTWerdenfels_Streckenkarte.pdf

4 nights in Salzburg

Day 9: Leave Mittenwald in the afternoon, 3.5 - 4 hrs. depending on train choice.

Days 10-12 sightseeing: Salzburg (find tips in the guidebooks.) Day trip by train options include Werfen (Eisiesenwelt ice cave, Hohenwerfen Castle and Falconry Show.) Possible day trip by bus to Berchtesgaden (Germany)

So, with Black Forest on the cards, I would skip Trier altogether - too much of a detour.
And I heartily second the recommendation for Europa Park in Rust. Quite possibly the best amusement park in Europe.