I agree with all of the above.
Another worth while trip is LaCoupal (not sure of spelling) at St.Omer.
This is a bit north and not a lot happens except at weekends,but this is actually my favourite airfield in the whole world! The people are very friendly,there is a lovely memorial on site and it is steeped in history having been the main stageing post for all British aircraft in the first World War and used by a crack German fighter unit in the Second World War.
The museum at LA coupal is where the V weapons were developted and well worth a visit. They have headsets available that give a running commentry ( in english) as you walk around and even have a cinema inside running war time films.
Oh and by the way,the beer is good at ST.Omer!! Nice restaurant on site,or go just up the road and sample the cusscus!
Camp under the wing or loads of hotels,nice market square with Cathederal and lots of eateries!
La Sappinier reccomended for a hotel.