for Port Antonio i would fly into Kingston and plan to fly out of Montego Bay
Moon San Villas sounds nice -- I would call them for a recommendation for a driver
I noticed the price from Kingston to PA is about $160 --- from Montego Bay it's ridiculous
To get to Negril you may want to try the Knutsford Express (bus). I've heard excellent things about it.
Some of the trip reports over here are very detailed and may help you with hotel and things to do.

Enjoy!