depends what you call better!
the NONstop CMX-HKT only runs 1/day in HIGH season (but thats now), but did not check it on new TG-Timetable, anyway it did NOt run last rainy times. If its off, and you have to change, then obviously dont bother with HKT.
IF you want the fun&adventure thai style: freq buses, as on every Thai main road, connect the 2, about ev 30 mins, alternating 2nd cl. and 1st cl. AC, via PangNga=James Bond rocks.
IF you want this do NOT take van/taxi all the way into HKT-town, rather hire Tuktuk to main rd/sala=shelter, and ask waiting people to point the right onstorming bus (there will be many), this aves the 2x20 mins in./out of same road.
BKk-Krabi is done by noth TG, by PBair and by Phuket-Air, combing 3-4 flites/day (maybe more now in high season), where youll need to hire a fairly expensive taxi (for thai standard) into town, or onward/boating to the beaches