Happy New Year!
Treadsection is complete!  The right tread contains the power supplies, 5 vDC @ 30 amps, 12 vDC @ 20 amps and 24 vDC @ 20 amps.  At this time I am not planning on a working soil sampler, that upgrade will have to wait!  These are Dana Covert's treadsections, Norm Sockwell's wheels & side panels and Dewey's treads.
Note that I used the upper wheel bolts to mount plates inside the treads, then I used pipes to form the actual leg supports.   Four larger diameter pipes attach to the upper section and slide down over the 4 smaller diameter pipes mounted to the plates in the treadsection.

These photos' should help explain how the legs connect:

• Back View of treads showing power cord and switch.
• Top View of treads showing leg support mounting plates.
• Side View of treads.
• Leg structure and treads before mated.
• Treads mated with leg support structure.
• All the parts stacked up.