You should mention on the help screen that the scroll wheel lets you zoom into first person/ engine hood view. Before you do that, those should be fixed though: The front shield is black, not transparent, so I could use only engine hood view. This is a bit too "dynamic" though, in lack of a better term. When you drive upwards, the camera descends below the engine block and I see the front suspension. When driving downwards, I look in the sky and can't see the car at all, makes avoiding obstacles difficult.
For the roads: To make driving a bit more challenging, add obstacles close to the road, e.g. guard railings.
For the generation: Right now it feels like a very even distribution of item scattering. Defining some types of areas and how these get populated with scenery may give a sense of "overall structure".
As a fan of Slow Roads, I do like this approach! Climbingin the mountains and jumping down was kinda fun. Maybe add a second car that is faster?
Well I hope you sell a lot of plugins so you can keep working on this :) Bookmarked and looking forward to updates.