You were invited to figure out what Mystery Spot 14 is using just these three rhymes and the fact that it's in a National Park-designated unit of the National Park System.

Two prongs that meet at Doubletop
Form a river that doesn't stop
Until it dumps its flow
Into the bigger river below.

and

My vacuum cleaner cannot speak,
And yet it shouts a clue.
If you could read what's on it,
You would hear it too.

and

An outdoorsy four-letter word
That you have often heard
Is an adjective, verb, or noun
Whether in forest, field, or town.

and

It isn't a White House, or a red or a green house,
It doesn't have clapboards of blue.
It's a Brown House, you see,
And preservationists agree,
That brown will just have to do.

Rhyme #1 identifies the place where the Rapidan River is formed by the confluence of two smaller streams -- Mill Prong and Laurel Prong -- on Doubletop Mountain about three miles from Big Meadows in Shenandoah National Park. The confluence is within Rapidan Camp, a 164-acre property that was purchased by President Herbert Hoover for use as a rustic rural retreat during his presidency (1929-1933). President Hoover prized this mountain retreat for its privacy, cool weather, lack of mosquitoes, superb trout fishing, and proximity to the White House (less than 100 miles away). He donated the property to the federal government in 1935 and it was incorporated into the new Shenandoah National Park in 1935. Although the property was named Camp Hoover for a time, and was designated a National Historic Landmark under that name, its official name was changed back to Rapidan Camp.

The second rhyme is especially helpful if the first clue has put you on the right track. The description fits the Hoover vacuum cleaner, one of the world's most popular vacuum cleaner brands. (In British English, "hoover" is a generic term for vacuum cleaner.)

Rhyme #3 provides the word needed to nail down the proper name of the mystery spot, not just its geographic site. "Camp" is one of the few four-letter words that is clearly outdoorsy, can be used as a noun (Boy Scout camp), a verb (I like to camp) or an adjective (I like camp art), and can also be combined with Rapidan or Hoover to specify a place location in a national park.

The final rhyme relates to the fact that, whereas President Hoover's residence in Washington, DC, was the White House, his Rapidan Camp residence (the President's Cabin) was facetiously dubbed the Brown House.