I want to build a path in the garden. It will run about 150 feet and be 3 feet wide. It will probably be flagstones set in sand (I am still looking at alternatives). My problem is how to excavate the base. I think I need to go about 4 inches deep to accommodate two inches of sand and roughly 2 inches of stone. A pick and shovel will do it, but I would like to know if there is some kind of power tool that would do the job faster and easier. One consideration is that below the grass roots my lawn is good old tough Virginia clay. I know I could hire someone to do the job, but I am retired and enjoy doing things myself.

I find references to sod cutters on the web, but they seem to work only to depths of 2 or 3 inches. Has anyone used one and made repetitive passes to increase the depth of the trench?

I also find references to backhoe excavators, but I wonder if they can be controlled well enough to do make a neat cut.

Any help from people who have succeeded in this kind of project will be appreciated.