Belgium/Netherlands Cycling Route Help

I am planning a bike tour for late summer/early fall. I am looking to do around 700 miles. I plan on starting the route in Lake Constance and following EuroVelo Route 15 and heading into Frankfurt. To cut some miles and to visit Brussels I am planning on taking a train between Frankfurt and Brussels. Once in Brussels I plan on continuing the ride back to the Rhine River and finishing in Rotterdam or Amsterdam. My planned route is https://ridewithgps.com/routes/49411917.

I would like to pass through Eindhoven to see the Van Gogh-Roosegaarde fietspad and think I have a good route through Antwerp to Eindhoven. I found the Tour of Holland (Ronde van Nederland) route which takes you southeast from Eindhoven to Thorn/Roermond before rejoining EV 15 (Rhine River) in Arnhem.

My questions:

1) Is it worthwhile to go through Brussels/Antwerp/Aindhoven or is it best to just stick to EV 15?

2) Is it worthwhile to go through Aindhoven primarily to see the Van Gough Cycle Trail?

3) Is there a recommended route heading north or northeast from Aindhoven to Wanssum or Boxmeer to save a bunch of miles vs. heading SE to Thorn/Roermond before returning north again?

4) Any other recommended modifications to the route?

Thanks,

Scott