Koh Chang just 4 hours by road from Bangsaray Villa. Certainly the best Island to visit local to Banagsray. Is it worth the 4 hour trip, Yes.
The Island is the third biggest giving you more to explore. Waterfalls and great vistas await. Getting around the Island can be treacherous on the other hand take your time on the roads. There are some steep declines and sharp bends all around the Island. That is to say caution is needed at all times. In The rainy season this is another level avoid these roads altogether.