Three Country Point

Yes, I have been there some time ago. I remember driving up from the Dutch side and parking. I think there is also road access from the Belgian side as well, but only on foot on the German side.
There appears to be an hourly bus from Vaals (Dutch side). I found info here: https://9292.nl/en/vaals/bushalte-drielandenpunt

It is effectively a hill which is a country park, with the official border marker at the top you can walk around. Totally open, you have to find the border marker stones to see which country you are in.

There is a website (in Dutch): https://www.drielandenpunt.nl/
I presume you have seen the Wikipedia article: https://en.wikipedia.org/wiki/Vaalserberg

• Travel by train from Brussels to Maastricht. This takes 1h 40 minutes and has a change in Liège-Guillemins
• Take bus 350 (runs every 15 minutes, in the direction of Aachen) to Vaals busstation (or bus stop Maastrichterlaan/Bosstraat). This takes about 50 minutes
• There is no bus from the bus station to the three country point. It is a 30 minute walk to the three country point. (the bus stop near the three point country is only served during holidays. That means until August 17th and after that a week in October)
• From Vaals bus station you can take bus 350 to Aachen in Germany (takes 15 minutes). Or the German ASEAG buses 25 or 33.
• From Aachen you can take a train to Bacharach (check bahn.com)

A day ticket for bus 350 costs 6.50 euros.

By the way... It used to be a four country point. Even the road is still called Viergrenzenweg (Four borders road)

Anothet option would be:
- train from Brussels to Eupen (in Belgium). (Once an hour, no changes, takes 1h 45 minutes)
- Bus 396 from Eupen to Vaals bus station ( once an hour, 20 minute change from train to bus, takes about 50 minutes)
- And from there the same advice as above.

Doing this, youll also travel through Moresnet, the former 4th country.

Hmmm -- think this may be a lesson for your son about the definition of "tourist trap" and the importance of prioritizing. But a lesson that's good to learn early in life.

How is the Three country point a tourist trap?

According to https://www.merriam-webster.com/dictionary/tourist%20trap a tourist trap is a place that attracts and exploits tourists or (on the same page) a place that attracts many tourists and that charges high prices.

Of course the Three country point is visited by tourists. That is what tourists do, visit attractions. But the place itself is absolutely free. Only the maze has a (small) entrance fee.

The only thing it, it is not close to Brussels, but it is close to Aachen. Whether or not it is worth the detour is something only the OP can decide.

Sorry. I used the term "tourist trap" to refer to a place where tourists go because ... well, because it's there and somebody said they should see it. For a three-hour detour I would want more. Yes, you are of course correct that it's the OP's choice if the time spent is worth it.

I'd be more interested in the town of Baarle Nassau/Baarle Hertog, near the Netherlands-Belgium border. Baarle Nassau is a town in the Netherlands where many sections of the town are still part of Belgium, where they are Baarle Hertog. Within these sections of Belgium there are small islands that are still Netherlands. Take a look at this google map.
https://www.google.com/maps/@51.4390623,4.9453861,14z
I reckon the Schengen Treaty and the Euro made life a lot easier in this town.

That's a good idea from Sam. Baarle should be easier to get to, and it has places to eat etc.
Point your son at this Wikipedia article: https://en.wikipedia.org/wiki/Baarle
And at this photo from the article which I have seen reproduced all over the internet: https://upload.wikimedia.org/wikipedia/commons/d/da/Baarle-Nassau_fronti%C3%A8re_caf%C3%A9.jpg
Lots more photos if you search the internet.

@Sam, the Netherlands, Belgium and Luxembourg had a passport union even before they invented the Schengen Area. It was created after WW2. But they still had customs for commercial vehicles until the EU single market abolished them (late 1980's?), same as still exists for non-EU Switzerland and Norway.

• Train from Brussels to Breda (NL). This takes 90 minutes.
• Bus 132 from Breda to Baarle (takes 40 minutes, usually runs once an hour)
• Take the bus back to Breda
• Breda to Bacharach by train, between 2 and 5 changes, takes between 5 hours and 6 and a half hours

Not sure if Baarle Nassau is easier than Vaals. Apart from the weird border, not much to see/do in Baarle Nassau.

We did this in 2012. We rented bikes at the Aachen train station and rode up. It was great as a bike ride, but I don’t think it is worth going up there just to up there. However, perhaps it would be for your son.

Thank you for your responses! This gives me great solutions and incite about what to expect. I talked to my son about the possibility of not going and it just about broke his heart. It has been his one and only request for this trip. The lesson is, I support his dreams regardless of what I want and everyone gets at least one thing on a family trip. We are so excited for our adventure (big or small). I really appreciate your help.