At this link

http://suvarnabhumiairport.com/en/ebooks

there is a free downloadable PDF tourist guide to the Khao Yai National Park тАУ not too far from BKK on the road to Korat. Also on this same page is a link to two additional guide books тАУ one for the Nimmanhaemin area of urban Chiang Mai and one for Phuket.