Watch the Working Man online guitar lesson by Bill Kirchen from 30 Hot Rod Guitar Licks You MUST Know
James Burton played a lick like this on "Milkcow Blues" with Ricky Nelson, then again a decade later with Merle Haggard on "Workingman Blues". It shows up in many ways by many guitarists and here's my take on it.
Hybrid picked, the first half has a nice alternating bass, the top strings moving between A and D chords. That in itself is a good rhythm part. So go ahead and hang with that for a while, then add the slightly wacky second half.