I've never had to leave a bike out on the trail, although there was one time when I got a flat tire and took the wheel off and held the whole thing on the back of a friend's bike while we rode into town to a tire shop to get the tube patched - so I guess I actually left it for about an hour. On that same trip he ran out of gas and I had to go find a source of gas AFTER I had hit reserve. I filled up, transferred fuel to his tank, then we both rode back and filled up again.
I think I'm going to toss a few books of matches in with the other stuff that I carry, and get some form of water purifier. I haven't put a lot of thought into being stuck out somewhere for a long time, so this discussion has been helpful in that regard.
__Scott R. Nelson, 2008 KTM 990 Adventure, 2001 Honda XR650L, Folsom, CA