The island itself is roughly oval shaped, taking about a day to a day and a half to cross on foot, travelling from east to west. To the south, high cliffs rise, protecting the island from strong winds and waves. A deep bay
cuts into the island to the west, creating an almost picture perfect vacation location. Warm sandy beaches lie between the water and the open lands and woods further inland.
Much of the island is covered with vegetation, ranging from open grasslands to thick forests with the occasional clearing within them. A broad path appears to cut the island in two, and there is no mistaking it: this path was man-made. While it is no asphalt road, it is definitely to neat to be a natural phenomenon.
Or in picture form, it would look roughly like this.
The sea around the island is mostly calm, but if anyone was thinking about escaping by boat they will find two big barriers. One is the mosasaurus that still swims happily in the sea around Vatheon, eager for any easy prey. It does not come close to the island, making it safe to swim in the seas near it, but the farther out a character goes, the more dangerous this marine reptile becomes. It has been known to headbutt and attack any boats that seem to linger for too long on the water.
And if characters manage to get past this fearsome guard, they will find another barrier in their way, namely... well, a barrier. In a wide circle around the island, another invisible barrier stands, similar to the one that keeps the water out underwater. Though this one is clearly designed to keep something in rather than out. The barrier seems to be endlessly high. There is no barrier above the island, however no matter how high a character will fly, there is no chance of crossing the barrier that surrounds the island.