Living 40km from Bruges I have driven many times to France following the mentioned routes. I like to suggest some places worth a (little) detour and are also nice settings for lunch or having a drink. For saving time, as Nigel already says there are many service areas with places like Flunch along the highways. Do not expect a scenic drive, especially the busy A1 between Lille and Paris is boring, but the A28 and A29 between Amiens and Rouen are much calmer and from a scenic point of view not so bad.
Veurne, still in Belgium along the E40 for it’s lovely gothic style town square. Further south of Calais along the A16 the historic centre of Boulogne-sur-Mer still having it’s medieval walls. Le Touquet-Paris-Plage, the area with old fashioned villa’s around the convention center is nice for a walk, the seafront however is ugly. Nearby fortified Montrieul is not a top destination, but has a certain appeal making worth a stop. Saint-Valery-sur-Somme is a lovely but touristic seaside village with a steam train.
Never had serious problems around Lille, but pass it most of the time late in the morning or late in the evening, so not during rush hours. Seen a very serious traffic jam a year ago during evening rush hour in opposite direction, was really bad so try to avoid that. Everybody is changing lanes at several places around Lille, what can be a challenge if you have to do the same. You can bypass Lille following E403 – E42 / A27 to A1. What I like to do after a few hours driving is drinking coffee in Arras. In April the unique Grand Place has plenty of parking space and nearby Place des Heros lots of restaurants and cafés. If the weather is fine my holiday starts actually there. Amiens is not only attractive for it’s gothic cathedral, but also the pleasant historic part of town around it.
Be aware that Rouen is busy and with all it’s many one direction streets not an easy place driving through, best is to know where to park before you leave Bruges even using a GPS. Likely you wil cross one of the large TEOR rapid bus lanes like the one running through Rue Géneral Leclerc a bloc south of the cathedral. The buses run fast, have priority and you are not allowed to use their lanes! I used Google Streetview before leaving home, it helped me a lot finding my way to the entrance of the parking under Place Saint-Marc.