Hi Bro,
A couple of years ago, while holidaying in Langkawi, I received instructions to travel to Bangkok for a meeting. No direct flights at that time from Langkawi to Bangkok. So I asked around, and decided to take a ferry to Satun, then travell about 85 km to Hatyai Airport and flew from there.
The whole journey worked out well, but I don't think it is advisable to do the same journey now with the political problems in the South.
There were quite a few ang moh backpackers on the ferry from Langkawi as well. Apparently, they were taking land transport from Satun to Krabi and then on to Phuket.
Satun is a small Muslim town. In fact, there are quite a number of Malays living there as well. Did not see much cheonging activities during my short transit in the town.