I cannot believe there are so few interpretations available online for this song.
The album also contains a song with "Dharma" in the title which suggests familiarity with a Buddhist context.
I see the song being about purpose and meaning in life, a worry about being able to carry on in today’s society, and a sub-theme about drugs, either literally or as a metaphor for the wider empty satisfactions of a materialist society. “One foot in the graveyard” refers to death and the pull towards giving up a hollow life, or on the other hand “one foot on the bus” with the rest of materialist society, who are empty of meaning, intent only to get their kicks how they can - useless to look to the “chicken-hearted lawman” as authority for leadership and support when everyone is beating a path to the doctor's door to feel better by taking the latest pill.
The second verse may also be implicitly Buddhist in inspiration: trying to love everyone is difficult when the ideals of the 60's have given way to cynicism, materialism and selfishness, Hypocrites still spout the hippy ideals while busy with selfishness, and whores who have sold themselves out; “drowning in the fountain of life” may refer to the attractions of the materialist world, or samsara as it is often called: how can they all be so callous and insensitive to the spiritual suffering of such a purposeless existence where I don’t fit in with all the bullshit; without meaning, life is purposeless and death is attractive, and the only way to cope is to take the damn pill again