What's the best way to get from BKK or DMK to Khao Yai National Park and/or the most affordable way? I'll by flying from Singapore back to Thailand so I can pick either airport. Also, where can I stay overnight in or near Khao Yai? My budget is USD $150/nt or less. Finally, is it worth it to hike in Khao Yai and can you swim beneath a waterfall there?

This is the Hiking Portion of my trip. My other thought is to head to Chiang Mai afterwards and do some hiking there. Would love recommendations.