I don’t want to go too bonkers over this Mark Sanford thing, but to be clear Josh Marshall is on the mark when he observes that to say someone is “on the appalachian trail” actually conveys very little information about that person’s whereabouts. The trail is over 2,000 miles long. If I said “I’m somewhere in the Boston-Washington corridor” that would arguably describe a narrower range of possible locations.
Actually walking the whole trail is something people do, I think, but it’s obviously a sort of idiosyncratic endeavor that’s not compatible with being Governor of South Carolina. Normal people who want to do a few days of hiking and camping will normally be taking trips to a specific location on the trail. In the summer of 1995, for example, I went to Mount Washington in New Hampshire. The following summer I climbed Mount Katahdin in Maine. IIRC, at other points in my life I’ve been to the Delaware Water Gap National Recreation Area and also part of the Appalachian Trail that’s in New York State. But in any case, if you were taking any of those trips you’d tell people where you were actually going, not just gesture vaguely and thousands of miles worth of hiking possibilities running across the entire east coast.