Best island in Thailand to spend 3 months?

Hello!

My husband and I just came back from Thailand and we are in love. We visited Bangkok, Koh Tao and Koh Phangan.

We would like to know which is the best island to spend 3 months, doing a local life. Here is what we are looking for:

- Super beautiful beaches and clear water

- Not a expensive place

- Some things to do, like maybe a mall if we want to catch a movie.

- Not so full of tourists, which takes away the real thai vibe

- Not so difficult access, since we are going with our little dog

- A vet clinic around is important in case of any emergency

- We would like to have a motocycle as our main way of transport

We would like to take this time to relax and embrace the slow life. However, since I was born and raised in Rio de Janeiro - a big city - I don't want to feel I am "closed" in a too remote place, if you know what I mean. But... The idea of "lost in paradise" is something that excites me. Is it possible to have it all? Hahaha

Thank you so much!