I have the classic "Fundamentals . . ." and several contemporary, with CDs, etc., as well as online sources. The problem is not observing the rules, it's finding them.
Based on the audio, several letters (T, P, etc.) are silent at the end, although the corresponding romanization indicates that they are voiced. The same audio provides formal ("krrahp") pronounciations for all words.
However, I've looked for a written rule on muted silent consonants and have yet to find one (although the rules for rr = l and l = m are easily found).
Thank you Brandon and Henning! I am familiar with consonant shifts (l = m) at the end of a word, as well as with "l" used for "rr" in spoken (but not radio Thai [kahp vs = krrahp].