Depends how picky you are in what trains to use and if you want to save money or rather time.

In DE=germany there is till aug a extremely cheap ticket for just 9€ till end of the month-and the long of your trips are in that country. LUX is free anyway. THis cheap ticket is ONLY valid in Nahverkehr=local trains, not the fast white ICE/IC. It also includes all local tram/bus etc.

You then prebook-and have to stick to those days/train LUX-P(French TGV)  and P-B and perhaps B-A.

BUT the last 2 legs on Thalys are hard to get (many trains out of service)and also cost a lot more as normal trains. B-A can be booked on local train untill 7 days before for lower price. OR use the BUS-FLIX for both these.

The first 2 legs In NL can be booked online without any discount via ns.nl and wont be cheap, nor is there a realistic way to cut the price. For R→ Köln: buy ticket at NS to Venlo-then find german machine in hall-beside kiosk (NOT the yellow NS-machine!) and buy the 9€ ticket from there (technically it is only valid from next stop=1st in DE-officially you have to buy a ticket for 2,70 till there: Kaldenkirchen too.

Dan selamat jalan yah! You are nomber satu to arrive in NL on this new ferry I´ve seen.

Thank you for giving me a very detailed information.

It definitely brightens the journey.