Driving in Belgium/ Netherlands

Brad, two comments:
1) Why a car? Can you not do this by train?
2) Picking up a car in one country (Belgium) and returning in another (Netherlands) usually has a high surcharge. Have you got an estimate for this?

Lille is the most southerly of your locations. A better order may be Brussels, Lille, Brugge, Ghent, Antwerp, Delft and Haarlem/Amsterdam.

You will get hit hard by the ring traffic around Brussels and Antwerp. These cities are much, much easier to hit by train.

We were a family of four and did a similar trip. Third day in Brussels, picked up a Mercedes sedan ( they tried to give us a Mercedes wagon for more space, but I wanted a trunk) and went off to Waterloo, Dunkirk, Flanders field, the north beaches, and your listed cities, ( and even further south into the Ardennes and Lux.), turning the car in near Vondel park in Amsterdam after dropping off the luggage. Yes, the ring roads are congested but otherwise simple to drive and more freedom to stop when something interesting pops up. Did not see a train station near Waterloo memorials, for example. And as for drop off fees, those are easily computed- perhaps $150 then- which is worth my convenience for out of the way places. We also enjoyed seeing Delft and Haarlem with the car. Great roads and get a data plan for your phone or a GPS for best results. (We used to use a handheld TomTom but this summer we had TMobile and the phone told us where to go on an Italian/Greek trip.)
By chance on that trip, traveling with teens and thinking it might get hairy in the car, I took the full insurance coverage and it paid off- a sheepish young man backed into the Mercedes at a light - it was driveable but $1800 worth of damage to the car- happy to turn it in and walk away. Enjoy your trip, we loved the area.

For Bruges, you can park at the structure at the train station, and you can use the bus free to go in to the Grote markt. Just show your parking structure ticket to the bus driver.

One thing to remember when you're driving in Belgium is that in Wallonia, cities are identified by their French names, while in Flanders, they use the Dutch name. So if you're traveling in Wallonia, the signs read "Anvers" and in Flanders they read "Antwerpen." Very rarely do they use both, so be sure you are familiar with the French and Dutch names.

I picked up my car at Gare du Midi/Zuid Station in Brussels and drove straight out of the city. It really wasn't too bad getting to the ring road from the station. Not sure if you want the whole family with all the luggage to travel to the station and jump in the car--if you're driving back to your hotel to pick them up, could be a challenge.

Gas stations took my US credit card--but your card must have a chip and a PIN. Even when the station was closed (Sunday morning), my card worked.

By the way, it's a great time to visit Brussels. The tourist traffic is way down, the museums aren't crowded, and the staff at the hotels and restaurants will be very happy to see you. Much of the central city is now a pedestrian zone, so it's much more pleasant than in the past.

Thanks for all the insight.