I guess I would like the most interesting and hope it is also the fastest. Thanx
Flying will be the best option. Have look on Bangkok Airways web site for flights and prices. If it is before 1 September 2018 then check also on Thai Air.
Fastest is flying non-stop with Bangkok Airways. Nominally one hour but more like 3 hours with check-in deadlines and wait for baggage. You might see something if you get a window seat.
Let's not go into the rat hole of how you could make the trip even more interesting than that.
I you fly and if the plane lands east to west in Phuket you a lovely view of Phang nga Bay! Its a quick 45min trip, and worth it.
Whilst a trip on the ferry / bus might be interesting after a couple of hours I could be boring. Its slower but much cheaper.
Interesting and best are very very subjective.
"I guess I would like the most interesting and hope it is also the fastest"
Fastest = flying
Interesting = the trips where everything goes wrong. Sucks at the time, but makes for a great travel story when you get home.
I would fly
Second the notion of flying.