One thing that can help memory (together with a journal of some kind, of course) is
The Rename. With this program it is easy to rename every picture (with any digital camera) to anything in the EXIF information stored in every picture. I have mine setup to rename pictures to YYYYMMDD_HHMMSS.jpg. That way, if I have forgotten where a certain photo was taken, it's quite easy to deduce from surrounding photos where every other photo was taken by knowing how far apart they were taken.
On this year's tour I'm bringing a small GPS tracker in order to make something similar to chrisch's gmap.