Rule 24-2 covers immovable instructions, which includes a cart path. A cart path is defined as an artificially-surfaced road or path. Thus this would not include a dirt path, so relief is not granted for that.
Relief is granted if the immovable obstruction interferes with the player's stance or swing. It does not include relief from the line of play (except on the putting green). So if you have to chip over, through, or around a sprinkler head, that's just the rub of the green.
For our last tourney, we put a local rule in place, granting relief from a dirt cart path.
The link below shows pretty well where you should drop.
http://www.golfdigest.com/story/rules-cartpath-drop
