First, the class will be re-named "Border Fighter," and being Good (remember, I'm swapping out Lawful and Chaotic) is no longer a requirement. There's nothing inherently "Good" or "Evil" about the skill set of this class, so it seems to me that since I'm not reproducing Tolkien there's no reason to require it.
Tracking is not done with percentile dice, but with the roll of a d6:
Outdoors the ranger has a 5-in-6 chance of tracking, this chance being reduced by one for every two days old the signs are.
Indoors the ranger tracks as follows:
|Monster's Action||Ranger needs to track|
|Goes down a normal passage||1-4|
|Goes through a door (normal or trap)||1-3|
|Goes up/down a chimney or shaft||1-2|
|Goes through a secret door||1|
In a city, treat empty streets as normal passages, moderately populated areas as "going through a door," and heavily populated/bustling areas as secret doors.