John Phillips is referencing a drug bust, being tricked by the authorities and his expectations of where he would be serving his time.
Sometimes I drive out to Topanga
And I park my car in the sand
Watching and waiting for a pickup
From my man
And maybe down to Farmer's Market
Those people, they're working in the sun
Buyin' and sellin' for a profit
To anyone
Oh Mary, I'm in the deep water
And it's way, way over my head
Everyone thought I was smarter
Than to be misled
You've heard of trainwrecks in the mountains
Sometimes there's shipwrecks on the sea
Mary, you must always be careful
Can't you see?
Oh Mary, I'm in deep water
And it's way over my head
Everyone thought I was smarter
Than to be misled
Some are sent to San Fransisco
Some go down in New Orleans
Others are kept in Camarillo
Picking beans
Oh Mary, I'm in deep water
And it's way over my head
Everyone thought I was smarter
Than to be misled