Tarutao recommendations for December?

Need to take my boss on his first Thailand trip in the peak peak peak
tourist season Dec 18-Jan 2nd. He says he wants to get away from
people. I say "good luck on those dates". I was thinking of Ko Tarutao
or Ko Lipe maybe? I've never been. I'm sure there will be plenty
people that time of year, but should be a bit less crowded than
average.

Is Ko Lipe over the top? I suppose it would be the one Island to find
things like A/C and swimming pools, which would be nice but not
mandatory. We may end up opting for a bungalow w/fan in order to get
away a bit more.

I can also try contacting the national parks office and see what info
they have.