Thanks for the kind words, Joe.

About the subjunctive:

"If it wasn't..." would not fit metrically.

The singer is trying to charm and reassure the lady. He uses correct grammar to show he's not a ruffian.

If you sing this song much, you will realize that the hard American r's are part of its charm. One's voice seems to bounce off them, as if off a trampoline.
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Cypress trees: there are native crypresses in the American South and in the Northwest.

As for the lines about his money and sleeping in the woods, keep in mind that he is a vagrant, a weakling, and a drinker who also happens to have a good heart. Don't take anything he says as gospel as he tries to cadge food and shelter.

Fortunately the Creole Girl knows how to deal with his suit. She plays the Fictitious (probably) Boyfriend card.