Hi David,
Depending on where you are travelling from the Eurostar via Lille or Paris is worth investigating.
While all the camp sites are fine I would recommend you trade up to Houx if you are on foot. Advantages are it is close to Tram for access to train and town and Carrefor (supplies) is close. The paddock village has bars and food service and plenty of spectating opportunities. Others can tell you the merits of BEAUSEJOUR but I can tell you with out a car or bicycle it is a loooong way from everything except the Porsche Curves.
Canada Phil