Cycling - yes, the immediate area around the site, and into the village is flat, good roads, and some cycle tracks through the woods also. You can walk into Argeles Plage (the beach bit, with loads of bars, restaurants, night market stalls, etc) along the beach, or you can walk into Argeles village (quieter, typical holiday village). The scenery inland might be a little too hilly for biking unless you are fit, but is stunning, with some lovely mountains and scenery. It's a very lively site, with activity all the time in high season, and busy even in low season but less 'frantic'. Traffic can be heavy almost all season, and the supermarket packed (bigger supermarkets in Perpignan and almost worth the drive, because it's so much easier!). Good pool and shower blocks etc were kept clean when we were there.
My son worked nearby, two years ago, for Canvas holidays.