The “sawdust trail” (or “sawdust circuit”) refers to the churches that preachers traveled to in the early 1900s. The trail to these tabernacles was usually covered with sawdust, and American evangelist Billy Sunday (1867-1935) popularized the term “hitting the sawdust trail.”
   
“Hit the sawdust trail” was cited in a 1906 newspaper. “Chautauqua’s sawdust circuit”—a speaking circuit—was cited in 1914.
       
 
Wikipedia: Sawdust trail
The sawdust trail or the sawdust circuit consisted of a series of temporary buildings or tents used by itinerant ministers for revival meetings.
 
History
Tabernacle floors were covered with sawdust to dampen the noise of shuffling feet (as well as for its pleasant smell and its ability to hold down the dust of dirt floors), and coming forward during the invitation became known as “hitting the sawdust trail.”
 
Wikipedia: Billy Sunday
William Ashley “Billy” Sunday (November 19, 1862 – November 6, 1935) was an American athlete who, after being a popular outfielder in baseball’s National League during the 1880s, became the most celebrated and influential American evangelist during the first two decades of the 20th century.
   
(Oxford English Dictionary)
sawdust, n.
With reference to the use of sawdust for strewing the floor of a place of public entertainment (as a circus, etc.) or (U.S.) the arena used by a travelling evangelist.
1864   ‘P. Paterson’ Glimpses Real Life xii. 120   As good as the general run of sawdust plays.
1883   Cent. Mag. 25 746/1,  I was not flattered at being taken for a sawdust artist.
1883   J. Parker Tyne Chylde 274   The sawdust ring of a bankrupt circus.
1902   R. W. Chambers Maids of Paradise xvii. 296   Once only they [the circus procession] circled the saw-dust ring.
1913   Collier’s 26 July 7/3   And down the aisle, ‘hitting the sawdust trail’, they come in ones and twos and dozens, until 476 have stood before that multitude to shake the evangelist’s hand and signify their intention of starting another life.
 
9 March 1906, Bureau County Tribune (Princeton, IL), “Sunday Bombards Dancing and Cards,” pg. 4, col. 3:
So it was with us, Sunday told us to stick and we stack. It was on Nov. 2 that I hit the sawdust trail for headquarters and I have been getting around on these impromptu legs as best I could ever since, trying to do my Master’s will.
Pg. 12, col. 5:
At the meeting for men only 118 men tramped the sawdust trail.
 
25 May 1906, Bureau County Tribune (Princeton, IL), “Princetonians Visit Freeport,” pg. 1, col. 2:
Last Sunday morning five thousand people were in the building; it will comfortably seat six thousand. One hundred and fifty people tramped the sawdust trail, aud three thousand dollars was raised toward paying for the building.
 
1 June 1906, Bureau County Tribune (Princeton, IL), pg. 12, col. 3:
Mr. Halladay is upwards of sixty years of age. aud he says that he did not begin to enjoy life until after he hit the sawdust trail and began to attend church, read the bible and pray.
 
25 October 1909, Cedar Rapids (IA) Evening Gazette, pg. 6, col. 4:
TABERNACLE FILLED WITH MEN; ALL MOVED
Two Hundred and Sixteen “Hit the Sawdust Trail” and Professed Christ.
 
23 May 1910, Bellingham (WA) Herald, “Revival Work Begins to Bring Big Results,” pg. 1, col. 1:
That the strong undercurrent of religion which has been started in Bellingham during the first five weeks of the Billy Sunday campaign is about to crystallize into definite results in the last seven days was abundantly shown by the results at the afternoon and evening meetings yesterday, when a total of 211 persons, including some of the best known business and professional men in the city, as well as some of the most prominent women in society, hit the sawdust trail for the penitents’ bench in the front part of the building.
 
28 May 1910, Bellingham (WA) Herald, pg. 1, col. 7:
77 Converts Hike down Sawdust Trail
 
Chronicling America
27 December 1910, Evening Times-Republican  (Marshalltown, IA), pg. 4, col. 6;
BILLY SUNDAY IN WATERLOO.
[Waterloo Reporter.]
(...)
Maligned without mercy he has proven the stories about him to be falsehoods and the campaign in Waterloo has witnessed the spectacle of many who were utspoken in his denunciation before his arrival “hitting the sawdust trail” and taking him by hand.
 
17 May 1914, Fort Worth (TX) Star-Telegram, pg. 8, col. 2:
Government at Washington gradually is getting under canvass. Several members of the cabinet plau Chautauqua’s sawdust circuit, and now the President has pitched a “big top” on the White House lawn for an executive office.
 
OCLC WorldCat record
Going up the sawdust trail
Author: Joe Burke; Al Dubin
Publisher: New York : Leo. Feist, ©1915.
Edition/Format:   Musical score : English
 
OCLC WorldCat record
Song stories of the sawdust trail,
Author: Homer A Rodeheaver
Publisher: New York, Moffat, Yard and Co., 1917.
Edition/Format:   Print book : English
 
Google Books
Billy Sunday, the Man and His Message:
With His Own Words Which Have Won Thousands for Christ
By William Thomas Ellis
Philadelphia, PA: The John C. Winston Company
1917
Pg. 158:
Imagine a lumberman lost in the big woods. He has wandered, bewildered, for days. Death stares him in the face. Then, spent and affrighted, he comes to a trail. And the trail leads to life; it is the way home.
 
There we have the origin of the expression “Hitting the sawdust trail,” used in Mr. Sunday’s meetings as a term similar to the older stereotyped phrases: “Going forward”; “Seekign the altar.”
 
Chronicling America
26 January 1919, Washington (DC) Herald, “Irene Was ‘Over There,’” pg. 4, col. 1:
Irene Franklin and her husband, Burton Green, have just “done” the sawdust circuit back of the Yankee lines in France.
 
OCLC WorldCat record
The sawdust trail
Author: Billy Sunday
Publisher: [Philadelphia, Pa.] : [Curtis Pub. Co.], 1932-1933.
Edition/Format:   Print book : Biography : English
 
OCLC WorldCat record
Sawdust trail chaplain : one man’s experiences as a military chaplain in war and peace
Author: Harry W Webster
Publisher: [Lafayette, Calif.] : [H.W. Webster], 1985.
Edition/Format:   Print book : Biography : English : 1st ed
 
OCLC WorldCat record
Down the sawdust trail with Billy & Ma Sunday
Author: Stephen Grill; Kathleen J Allison
Publisher: [Winona Lake, Ind. : Morgan Library], Grace College College and Seminary, [2011].
Edition/Format:   DVD video : English
   
The Saline Courier (Benton, AR)
Salem Camp Meeting: Sawdust trail just a memory, but old-time religion goes on
By: Lynda Hollenbeck, Senior Editor .(JavaScript must be enabled to view this email address)
Monday, June 6, 2016
SALEM
Camp meetings, once a popular form of worship in this country, now are few and far between. But the tradition is more than a memory in Saline County, which is home to the continuing Salem Camp Meeting.
(...)
The phrase “hit the sawdust trail” was coined by one of America’s most famous evangelists, the late Billy Sunday, who used the metaphor throughout his career. He would tell his audiences to “hit the sawdust trail” and give their lives to Jesus.