He went through Montreal at least twice, the first time in 1917, on a train and the next time, in 1957, in his hand-painted automobile.
At every town he hit, he tried to get media attention with his fast-painting act and frequently succeeded. (No doubt very much a predecessor of Bob Ross style painting)
In Montreal he told a local reporter that a hobo is a working migrant, a tramp is a non-working migrant and a bum is neither, he's just a sponge.
Hubbard was born in Bowie, Texas in 1892, served as a private in WWI (but not that long if indeed he came through Montreal in 1917) and never married.
Newspapers loved reporting on Hubbard and National Geographic reportedly did an article on him sometime in 1937 or 1938.
https://www.flickr.com/photos/floridamemory/9608607666
https://thebrooklyncollection.tumblr.com/post/93442086807/self-styled-hobo-artist-paul-hubbard-an/amp
That little boy in the picture of Paul Hubbard and his beautifully painted car is Martin Abrahams. I am presently 70 and lives in Houston Texas. Hubbard gave him lessons in painting and wonderful stories about life. He made three gigantic murals in his dad's house
Paul Hubbard, known as the Hobo Artist and a muralist, painted the interior of the Pequot Theater in New Haven Ct. Opened by 1914 and closed in late-1950's, it was later converted into an auto store then demolished
Update Oct 17th, Karen C found TWO Hubbard paintings at a garage sale!
Thanks Karen!!
From: Popular Science, May 1959, page 133.

Update May 2022, Sarah was cleaning out her grandpa's place and found this Hubbard:
thank you Sarah for sharing!
Update Dec 10th 2022, Richard found this 1954 painting, that his wife's parents bought it on their honey moon in 1954, and it's been in storage for 30 years
And Victor emailed me, and sent me a photo of the painting that Paul Hubbard did for him!
Victor met Paul in South Dayton Florida in '59. He painted a picture for him and gave Victor a lesson in mural painting. Victor was 14 at the time.
Thank you Victor!