Help me plan a (road) riding holiday around Picardie / Nord Pas-de-Calais / Southern coast of England

I have a real hankering to cross the Channel using https://www.saillink.co.uk/, a sail-powered catamaran that takes foot and cycle pasengers between Dover and Boulogne-sur-Mer. Might as well take the tandem and do some riding while we're over there, but it's not an area with which I'm familiar so I thought I'd ask here in STW where inevitably, it will turn out that someone was the local cycle touring planner for 20 years or something, or at least there will have been a few people who've holidayed round that way

Anyway, I'm thinking of a week or so in late August / September, travelling out on a Saturday and back the following weekend. We usually do point-to-point touring, covering 50 - 70 km per day, but equally we've had trips where we've based ourselves in one location and ridden "from home" each day.

I've had all sorts of vague plans

- a circular tour taking in Arras (lovely town, we've visited on overnight stops when driving back from the Alps) and Ypres (which we've visited by bike and loved)

- ride inland and rent a gite for a week, with day rides out

- maybe a circular tour visiting the WW1 battlefronts

- ride the VeloMaritime down to Dieppe and get a ferry to Newhaven, then ride back to Dover (could obvs do that anti clockwise too, depends on saililng times)

- something else?

We'll mostly likely be riding the electric tandem, a Moustache Samedi 27x2,  so we could increase the distance - previous tours have all been on manual tandems. We probalby won't have a lot of gear as we'll only have two panniers. Happy to stop in one place for a couple of days to allow us to e.g. wander round Arras / Ypres / another lovely town, and to meander around en-route to visit interesting spots (we called in at Tyne Cot on the ride from Ypres to Ghent, well worth a detour)

So, over to you, the STW cognoscenti. Sensible / humourous suggestions, please!