Hm...a problem with the idea of a 'champion of the wilderness' is that there already is a class for that. Actually, there's two classes for that: Ranger and Druid. I'd sort of suggest taking a ranger with favored enemies of Undead or Abominations, actually.
Assuming you really want a paladin, I'd focus on destruction of unnatural creatures (e.g. undead) and defilers of nature, and probably relatively less focus on being an exemplar of good as opposed to a destroyer of evil.
Assuming you really want a paladin, I'd focus on destruction of unnatural creatures (e.g. undead) and defilers of nature, and probably relatively less focus on being an exemplar of good as opposed to a destroyer of evil.