Book about a boy that joins a traveling "snake-oil" show and eventually escapes, finds his father?

Question

I used to have this book about 20-ish years ago.

• Setting for the story is some time around the gold rush
• Boy runs away from home (possibly an orphanage?), a man on a traveling wagon offers to hide him from searchers.
• The man turns out to be a "doctor" who sells a fake "cure-all" potion / elixir as a traveling snake oil salesman. At some point the boy is put in charge of mixing the potion and realizes there is just a lot of pepper in it to make it taste strong.
• The "doctor" introduces the boy to chewing gum at some point
• They travel around, set up in mining towns and have a bit of a show, with the goal being to fleece people out of their money by selling the fake potions.
• One wagon contains a blind strong man who is forced to perform by lifting extremely heavy weights (but not as heavy as marked). I believe there is at least one other performing member of the troop who does a juggling act.
• One of the "doctors" cohorts is a man who is really good with a whip, likes to kill small birds with it.
• The boy is essentially held captive by some sort of threat, has to "help" the show with singing at first, then forced to learn juggling with "encouragement" from the whip-man, so that he can join or replace the juggler in the show.
• Often they are chased out of town once the potions are found to be fake.
• Eventually he escapes and is chased by the "doctor". If I recall correctly, he carves a hole into the bottom of the wagon (locked for "safety purposes") and drops out onto the road. I believe the "doctor" chases them into a ravine, and the strong man lifts the boy up the rock wall so he can escape and remains behind to deal with the "doctor" and whip-man.
• I believe the boy somehow finds his father? who helps him expose the show and during the large ruckus they rescue the blind strongman.
• I want to say it ends with them somehow owning a small mine that ends up having enough gold that they can live comfortably.

Hoping that's enough to identify this book, would love to read it again!

Answer 1

The Black Symbol by Annabel and Edgar Johnson

The Kirkus review is:

Barney Morgan, slight for a boy in his early teens, finds that he has what it takes to be a pioneer in this story of gold prospecting in Montana. When news reaches the boy that his father has perished while on a prospecting trip, he is convinced this is untrue, and sets out across the Montana territory to find him. En route he meets a medicine man and becomes involved in his troupe. Exploited and virtually imprisoned by the charlatan, Barney, with the help of Sampson, a blind strong man, finally escapes from the medicine wagon and together they reach Butte where Barney's father welcomes them and exposes the fraudulent medicine show. A fast paced story with a vivid, detailed, and unusual perspective of the Montana territory, prior to the advent of the railroad.