First time visit to Thailand (Phuket)

Hello,
Me and my husband will be travelling Thailand between 25 october -9 november.
It will be our first time in Thailand and we want to see the beauties as much as we can during our journey.
Since i am the one responsible from planning our tour, i would like ask a few questions to expatries/natives lives there..
We will be in Bangkok for 3 days and then want to go Chiang Mai by night train. And we will stay there for 6 days.
than we want to go the southern part but i can decide which side i must prefer the souteastern or southwestern part due to weather conditions since we will be there on november 3 till november 9.
According to my searches Phuket ( western side ) could be less risky for rain.
and the hotels in booking seems a bit pricey. what do you suggest?
any advice will be appreciated.
Thank you internations community:)