This was a bit different from the mini bikes available at the time in that it was foldable. Using a mini bike as a trail bike is nothing new. The Wilhelm brothers and others were utilizing them in the 1960's. Maybe before then.
From Archery magazine, August 1969.

What a great option to an ATV.
Thanks to a total knee replacement last year, I am more mobile on two feet, but then I rarely hunt more than 1/2 mile from the car
Living in the city back then the idea of using one of these for hunting would have been a novelty.
Yes, they were Chuck. I had one about 1962 when I lived in New York. My friends and I terrorized the neighborhood. Great fun! It was hand built by the owner of a used car dealership. 3 of us pitched in and bought it from him. The engine was a Briggs and Stratton pirated from a lawnmower.
Back then....i bet they were noisy cusses.
This is Johnny and Dead Eye and their minis in Yermo, CA 1960.
Here's one used by Walt Wilhelm in Yermo, CA. Not dated, but with the info from the next photo, likely 1960.