I drove one of those once. If you've ever driven an Air Cooled VW Beetle you've driven a Tri-Magnum. It uses a VW Beetle front suspension and steering assembly. It's essentially a simple, one peace bolt on unit. Whoever designed the Tri-Magnum made sure the wheel base was exactly the same as a Beetle as well. This ensured the steering would be safe and sane. It's easy to buy and install an adjuster on the top torsion bar to compensate for the reduced weight of the new body it's used with. Due to the number of VW Beetles produced and the continuing popularity it's easy and cheap to buy parts or even an entirely new manufactured assembly ready to bolt on your project.
Here's a picture of a complete front end assembly that's ready to go.