Help with animation of BMX riding on track.

Hello! I am doing a real time visualisation of a local BMX track which will be built next year. It comes out really good for me. But I would like to try put some life in it.
I gess there would be a number of approaches to get a rider into track, but I would like to make that as as reusable as possible. Maybe there would be a set of animations
sequence, rather then animated somewhere else completely just for this track only. Not sure that it would be easier, but maybe it could lead into more realistic result
and flexible workflow, and it would be possible to make full set of riders racing eachother on the track.
Another problem is to figuring out best approach for rigging. Weather bike and rider should have independant mashes and rigs and somehow glue them together.
I am taking in mind that bike should be affected both from surface of the track and rider, so maybe bike it’s self should not be animated, but then there are moments,
when I would like to control bike or leave it dependant on rider and track.
I hope, this tread could grow into interesting discussion which would help to also other developers with similar tasks.

This video could be very good reference

Another good reference