Following in the vein of super-villains with problems...
I am an anonymous villain (the best in my world), and have recently bought some new land and am in process of building on it with the intention of making it my main residence.
This land is in the form of a peninsula, and I own the "island" part, the "straight/connecting" part, and a few hundred square metres of the mainland.
The "connecting straight" is quite a few kilometres long, enough that the island part is decently separated from the mainland. At its widest part it is over a kilometre, and at its thinnest it is around 300 metres. Also, the "connecting straight" is not totally straight, at one point it has a 45/50 degree turn. It has a few trees and/or bushes, but is not thickly wooded. There are also a few rocks strewn around.
Now my problem is, how to prevent access without making it obvious? Obvious in my mind is men traipsing round the place toting guns. I don't want anything less than military (say a few tanks/people carriers) to be able to access.
I will have a fair few visitors, which would fit into two categories. The first is the "hires", men which I hire to do my dirty work. These would arrive via land. Second would be important people I invite (such as the president, who believes me to be a good guy), which would mainly arrive via my yacht, picked up from the capital.
The capital is about an hour or two boat ride away, and the area around the island/peninsula is very sparsely populated.
So what can I do? Looking for suggestions that are within the realm of possibility in this world (as mine is almost a mirror copy), but can be very technologically advanced, and money is of no object. The time is present day, or a maybe a little in the future if it helps.