Thanks Mike,
There is a standard security fence along the perimeter however at the end of the runway it's replaced by coils of razor wire hidden in the long grass and a well hidden moat - well a trench full of weeds and quite possibly alligators

Having eyed it up myself I reckon it would take a good 3-5 minutes to get onto the runway assuming there are no extra "features" hidden in the long grass...
There are that many spotters there that anyone trying anything cute would be dealt with quickly, that and the tower are always watching.
Phil
FlyingColours