modal verbs - "Would", meaning "possible or likely"

I don't often come across would meaning "possible or likely".

But when I was back home on vacation several days before, my college textbook gave an instance:

I recalled Blanche DuBois's famous line: "I have always depended on the kindness of strangers." Could anyone rely on the kindness of strangers these days? One way to test this would be for a person to journey from coast to coast without any money, relying solely on the good will of his fellow Americans. What kind of Americans would he find? Who would feed him, shelter him, carry him down the road? (From The Kindness of Strangers, written by Mike Mclntyre)

The reference book for teachers said these would meant "possible or likely" here. Was the textbook right?

If so, why not use "could" or "might" instead?

Answer

The original text

The tenses used in the quoted passage gave me a little trouble trying to follow the scene. Being curious, I searched the web, and I now believe that your text was adapted from Chicken Soup for the Soul: Unlocking the Secrets to Living Your Dreams, page 124.

Here is the original text, three paragraphs in full, with the differences highlighted:

    I thought of my destination--New Orleans, the setting for Tennessee William's play A Streetcar Named Desire. I recalled Blanche DuBois's famous line: "I have always depended on the kindness of strangers."
    The kindness of strangers. It sounds so quaint. Could anyone rely on the kindness of strangers these days?
    One way to test this would be for a person to journey from coast to coast without any money, relying solely on the goodwill of his fellow Americans. What kind of Americans would he find? Who would feed him, shelter him, carry him down the road?

The missing part is perhaps not absolutely necessary, but having it would make it much easier for us to follow the thought (and of course the narration) as indicated by the tenses.

Explanation

^{To simplify the explanation, I will talk about the time the writer was writing this essay in present tenses.}

I thought of my destination--New Orleans, the setting for Tennessee William's play A Streetcar Named Desire. I recalled Blanche DuBois's famous line: "I have always depended on the kindness of strangers."

In this first paragraph, the story is told in the simple past, which is consistent with the tenses used from the beginning of the essay. (The first line of this essay is "One summer I was driving from my hometown of Tahoe City, California, to New Orleans.")

The kindness of strangers. It sounds so quaint. Could anyone rely on the kindness of strangers these days?

This changes everything. The part "The kindness of strangers. It sounds so quaint." interrupts the flow of thoughts in the past, and shifts us back right to the present--the time the writer is telling the story. This makes it clear that the writer is asking such a question ("Could any one ...?") while he is writing that paragraph. He is thinking about the possibility of such thought, so he uses could.

One way to test this would be for a person to journey from coast to coast without any money, relying solely on the goodwill of his fellow Americans. What kind of Americans would he find? Who would feed him, shelter him, carry him down the road?

This is an example of hypothetical thinking. Let's consider each sentence separately.

The first sentence, "One way to test this would be for a person to journey from coast to coast without any money, relying solely on the goodwill of his fellow Americans." is written in the present time. He is making a real assertion. He can use will instead of would, but he makes it "less assertive" by using would instead. This can be read as he is quite open to other ways (to test), or he is less sure about the test.

The second sentence is a hypothetical (unreal) thought. Once he assumes "what if" according to the first sentence, every would after that indicates "unreal thinking": What kind of Americans would he find? Who would feed him, shelter him, carry him down the road? -- The tense usage is similar to those in the "present unreal conditionals", for example, "If we tested so, what kind of Americans would he find?"