Hunting major travel routes is the only surefire way of catching early season bucks in pattern. Deer are creatures of habit and will continue to use the same patterns until an external stimuli is produced (i.e. pressure). The best way to get on to a mature white-tail prior to the rut, is to find their travel routes and wait for all the necessities to align themselves. Perfect wind, temperature, time... Once those are present you should have no problem harvesting a mature timber pig.