Although the "Mad Scientist" is one of my favorite characters - both because he has a talk method and because I sort of identify with him - I had never actually looked at the texture before. I have to agree it is quite confusing.
In addition to having a fairly complex hierarchy, a necessary characteristic for a flexible character, the glasses and the feet seem to be all black so it's hard to guess what part of the texture map they correspond to.
In cases like this, I'd suggest starting with the top level object with no texture and with a solid color. Work your way down through the hierarchy changing the color of each sub-object as you go to make sure that you have a good idea of the actual object structure. Viewing in wire-frame mode during these steps can also be useful.
It is also a good idea to frequently rotate the object a full turn as you are working. Sometimes the lighting makes the color a sub-object look much darker than the texture - look at the difference in the lower legs in the front and side views in the attached.
Working this way, you can also often see that you don't actually have to go as far as editing the actual texture - you can get a lot of effects just by mixing a color with an existing texture, again as shown in the attached.
A final note - if the texture is very dark, such as the glasses for the Mad Scientist, you will have to go to "none" for a texture before the color will show.
Hope this helps. Good Luck.