Some things to consider:
Stay out of big cites. Average speed is -5 mph & you will get lost every 3 blocks.
Amsterdam to Delft. I think the tour of the porceline factory is free & the demo of hand painting the designs is impressive. Then visit the city center.
Windmills. Cross the Rhine south of Rotterdam. I little ways S alrong the river is the world's greatest concentration of windmills & some are probably open for a visit.
People who have visited both the Rhine Gorge & the Mosel Valley generally prefer the Mosel, which shoots you straight at Paris. but it's a long slow road. Take the expressway just N of Koblenz to the west, parallel to the river to the intersection expressway that branches off to the south & cross the Mosel. The bridge is about 500 ft above the river. Just across the river, exit the expressway & drop down to the river road.
Well preserved castles at Cochem & Burg Eltz. Cochem castle has a small collection of suites of armor including the largest ever suite of armor. Cochem is also a cute village, but just a warm up for Bernkastle. Vory twisty road from Cochem to Bernkastle. Consider taking the kids on river boat with one adult going ahead to the next boat stop in the van. Otherwise, there may still be some ferries operating here and there to cross the river. Do that for a diversion.
Bernkastle: One of the greatest quaint villages in Europe. Parking along the river. For a culinary treat, when facing the river in the town square (the quaintest town square in the world) face the river. Somewhere off to the right on one of the 4 very short streets between you and the river is a hole in the wall wurst stand. For lunch or a snack, get a bratwurst mit senf and brot to go, which is the only way to eat there ("and" is not the proper German room but the stupid automatic spell check won't let me use German). .
On to Trier, oldest city in Germany and one time capital of the Roman Empire. On the main drag near the Roman Gate (Porta Nigra) , note the house with the front door on the second floor. For security, they used a ladder to get in and out, and then pulled the ladder up at night.
The throne room is all that remains of the Roman Emperor's palace, now a church. Note it's size, and tell the kids this was just the Emperor's office.
The Trier Coliseum. In some ways more interesting than the one in Rome because it's been restored. Be sure to go into the basement where the wild animals & gladiators were kept before going up to entertain the bloodthirsty mobs.
Ecclesiastical architecture: You probably saw some austere. protestant churches in Holland. Trier Cathedral is good .
example of Gothic & there is a Baroque church a couple blocks NE of Porta Nigra
This should leave you with one day or a half day to get to Paris.
I forget to mention that the scenery is the main reason to travel the Mosel Valley.