I suggest you fly DVR-KONAN-KOK and before crossing KONAN you will have to contact Ostend Radar on 120.60.
They also control Koksijde CTR as well and know about the military activity.
After KOK you request a direct to EBKT, if the restricted areas are not active you will be told, if they are active, then a small detour to MAK and EBKT will do the trick.
Direct from KOK to EBKT will put you overhead EBMO, a very active paradrop zone that you have to avoid.
Outside of Ostend TMA, Brussels Info 126.90 will take good care of you, they see you on radar.
Don't worry about the extra overwater distance, Koksijde Airbase has SAR Seakings 24/7. I usually fly just below the airway at FL55 or so (from memory, so check).