I like the portal ideas.
What, if you could generate these “levels” based on a gpx file? So you could drive private gpx levels. And for public use:
First iteration with these blinky puffy syle set.
Second iteration, with trees, flowers, landscape etc.
This would be one step to be able, to virtual race real events in parallel.
Imagin if you could “race” a tdf etappe with others on your level. So you could do tdf, while watching tdf.
What donyou think?