Arras is slightly further, but is worth a trip in itself.
Two old squares with a decent market om (Fri?). At the citadelle there is a CWWG. Has a tiny car park adjacent. Nowadays you can either ride or walk round to La Place des Heros, where fighters of the Resistance were shot, there are plaques on the citadelle walls to give you their names.
Never actually stayed in Arras, but it is large enough to have a range of hotels and restaurants. ViaMichelin will present you a swathe of price ranges for both eating and sleeping, or check Booking.com
Nearby Arras is the famous Vimy Ridge. Bequested to the Canadian Govt in appreciation of the sacrifice of the Canadian Corps who stormed the Ridge, Easter 1917. One highlight is the Grange highway, the system of tunnels built o provide shelter and storage for the reserve troops and an easier passage for the fallen.
Every time I go the guided tours are slightly more regimented. Perhaps some of the tunnels are not as stable as they were. Take warm clothing.
Up top there are actual trenchlines, shell craters and allegedly lots of live rounds - but they are all behind fencing...
Vimy was perhaps the first attempt to use what are now considered "modern" infantry tactics by the Allies. Better thought out creeping barrage, outflanking by infantry and zut alors - telling the PBI what their objectives were!
Well done General Byng, and the Canadians.
The museum at Peronne is great, one of the best, as mentioned
If you wanted to go a bit further, then Verdun is very moving, and quite an extensive battlefield, apart from the regrowth, it is easy to imagine the layout. Several of the forts are visitable, the huge necropolis and a not too large museum on the "circuit".
A couple of acceptable bistro places in Verdun itself. A Ibis Budget, maybe others available on the edge of town
If only wanting a bimble along the coast there are lots of mostly WW2 blockhouses, rocket sites, museums down as far as Boulogne, You could consider going as far as the CWWG at Etaples, site of the infamous "Bull Ring". The ride along the coast is perhaps more interesting than the CWWG?
However Boulogne has the advantage of a slew of worthy restaurants.
La Matelote opposite Nausicaa - a destination in itself if the weather turned rubbish. They are also a hotel, and offer the occasional deal, room and dinner.
The ever famous Pecheur du Mer opposite Place Dalton. Good, but not my first choice.
My favourite, L'Epicure on the right as you get on to the main drag in Wimereux, inexplicably often empty, but the best food as has ever come to my table. Their €25 and €35ish menus are incredible value. The best excecuted, seasoned balanced and presented meal ever - and I have been to much higher rated places. The wine is decent value too, if in doubt, Virgine's recommendation will be good.
Hotel Atlantic, Le Leige restaurant (expensive) and the Bistro, which if clement goes outside onto the seafront.
Hamiot's in Boulogne has lost its way as far as good value is concerned, OK for a beer, but the food while not horrid, is to ordinary and not good value in my book.
La Chaloupe up as far as Wissant is a good bistro, star turn is the fish soup/stew - I think you have to have at least a two'er.
There are several others which I can dig out, if anyone is still hungry.
If the thought of so much death and needless destruction is all too much then there is the Musee Matisse at Le Cateau-Cambresis. Horrible parking in a car though.
Nick