Van
Vans are a great alternative - or, in many cases - your only option - if you need to travel overland within one and the same province or neighbouring provinces or states. Vans ply the roads between Krabi and Sirinat National Park, too.
Things to remember: When travelling by van with huge luggage buying a separate seat for your suitcase or backpack is a good idea. Do not expect there is a roomy luggage compartment in a van - there is actually none and your fellow passengers are unlikely to appreciate your luggage stuck under their feet, alas.
Companies operating vans between Krabi and Sirinat National Park
Green Planet, Thubthim Siam Travel