Large portions of most PMAs contain no trails at all and access to most of the lakes requires bushwacking and absolutely reliable orienteering skills. Plan accordingly and pack light. Previously established campsites are not maintained and are not identified on current maps. Latrines and firegrates might still be present but are being removed from those campsites. Most portions of PMAs have never contained designated campsites.
Old maps can be useful in identifying where portages and campsites once existed.
Fires are not restricted to firegates. I presume this happens when you pick up your permit. Each PMA is divided into sub-zones. Only one group is allowed to spend each night in each sub-zone. Human waste should be buried 6-8 inches deep in organic soil 150 ft. from shore.