Level 1: In town trail - city streets, maybe
some stairs and city squares.
Level 2: Urban, some off-road shouldn't need a dry bag.
Level 3: Some ready made paths & some trail blazing maybe wet.
Level 4: Mostly wooded trail blazing, could be fences, walls, homeless camps, garbage dumps, mud, muck, broken glass, snakes, spiders, little furry animals, swamp & water you could wade through!!!!!
Level 5: Anything goes: briars, stinky mud that could keep your shoes, plenty of water - some possibly over your head, beware of animals including snakes, possibly alligators, over all one that you should have a trail buddy with you.