The game is indeed still under development :) It's not my full time project and we recently had a child so I got a little side tracked. The good news is that a new release will be available in just a few weeks. It will include several improvements and a new desert/arid environment with many kilometers of trails to explore. The current map will also get a makeover with new defined trails (so as to not get lost).
VirZoom is actually coming out with a sensor that attaches to the pedals of any bike late 2017. They also have a c++ SDK available upon request so ideally I won't be needing to hack it in and full support will be possible/is planned.
On the handlebar tracking: I don't currently have a bike I can test with for turning, but tracked controllers are supported in the upcoming release. I mount my vive controller to my handlebars with velcro wraps. Brakes will be controlled with the trigger and the face buttons will allow easily getting out of tight spots (reset position, reverse, etc). Making steering happen is definitely doable. If enough people want it and are willing to guinea pig then it'll make it on the feature list.
Feel free to try the demo. Any early access purchase version you get will entitle you to all future releases on itch.io and Steam.