Mapping minor/informal trails (and other "walking path" questions)?

Something that I’ve been wanting is a source of maps that include relatively minor paths where one could (for example) go for a nice walk in the woods.

I’m thinking here of paths that are not formally designated or mapped, but things like overgrown logging roads that are still used occasionally by hunters or “casual explorers” like myself.
Is there a point at which a path becomes too minor to be appropriate for inclusion in OSM?

For example, I believe I have some tracks through the very southern tip of Sam Houston National Forest (near Willis, TX) where I had been exploring while walking my dog, several tracks
of which appear to be abandoned and mostly-forgotten remains of logging roads/trails, often somewhat overgrown but which appear to still be used occasionally by hunters (and are still reasonably clear “paths”).

For another example, where I am now there is a small collection of trails crisscrossing a wooded area nearby that gets used by offroad bikers, ATV riders, and snowmobiles in the winter.
It’s a pleasant place for a short walk, but as far as I can tell so far has no “formal” designation as a recreation area (“access=permissive, surface=ground” if I’m interpreting the tags
that ought to be used correctly). Is this too minor to include, or should I go ahead and start mapping?

There’s ALSO an urban walkway in town here - a loop that in several places overlaps existing roads/sidewalks. (This one is a real, formally-designated path/trail, so I assume its inclusion in
OSM will be appropriate). I’ll be mapping that for practice - can I assume it’s not going to cause a problem being overlaid in places along existing roadways?

OSM allows for some pretty “disused” tracks, see
http://wiki.openstreetmap.org/wiki/Key:tracktype

I would suspect that an urban walkway would be highway=footway http://wiki.openstreetmap.org/wiki/Footway