if you can find even a distant family member's grave to visit it does make it more poignant - a couple of years ago DH and managed to track down two great uncles, both called Percy (one on each side of the family) who were killed within a few miles and a couple of months of each other in 1917. (EDITED TO ADD - I had been doing some family history research) One was buried in a tiny, immaculately kept cemetery by a rural side road south of Ypres: the other in a military section of a municipal cemetery in a suburb of a French town... Check
https://www.cwgc.org/ to see if there is a known grave
We also visited the Menin Gate, the Canadian monument high on Vimy Ridge, a vast German cemetery, the fascinating museum at Ypres (a lovely town, with cobbled streets, walls to walk round etc) and a couple of other sites where you could explore old trenches etc (One more carefully manicured than the other...). I think we also visited another fascinating site near Arras where tunnels were constructed to break the siege
But after too much of this the weight of history can become overwhelming even for adults with an interest so be sure to look for some other things to do. Possibly chocolate related?? We weren't travelling with children/teenagers but I'm sure others will have suggestios