The nicest wooden walkways I've seen were built with two by fours, or two by eights, cut into two foot sections. Three foot lengths can be used, as well if you have the space, depending on the size of the walkway.
Use a sealent like thompson's or similar on each board, and color with a nut brown finish, or use a sealent with a nut brown color, as it gives a nice look.
Then dig a shallow hole for each board, spacing them about three inches apart throughout the walk way.
All done :)