Knowing very well the type of terrain you will be covering....
I would go with a Toy truggy...just the cab with dovetail front end, full exo, and flatbed/tube rear. There is something to be said about being able to escape the elements...especially the heat in the desert.
Like this build...without the boggers...would handle the So Cal desert and almost anywhere else
http://www.pirate4x4.com/forum/showthread.php?t=578044