Well, it's really a theoretical concept track, in other words it's just an idea that took my fancy. But since I have no room to set up a track, nor any digital track or cars, it's likely that I'll never have to deal with the practical realities.
But I guess you'd have to make it flexible enough to deal with all the different uses it could be put to.
For instance, the main two lane track could be used for a six car digital race, so you'd maybe want to make the main course visually obvious, perhaps by using white lines around it. The pit lane would also probably need marking out, and perhaps any devious short cuts would need a barrier or bollards to prevent any cheating.
At the other end of the scale, if you were using the track for a slot-nav, then obviously you'd want all avenues open, as the whole point of that is that you can actually take a wrong turn.
Or if you were creating a hybrid Scooby Doo/Cluedo/Scalextric gameplay hybrid, then you'd obviously have lots of signposts misdirecting you, the alluring Miss Scarlett stood outside the village pub, cards in the middle with the murderers name in an envelope, and obviously someone would have have to say "I'd have got away with it if it wasn't for those pesky kids."
For me, it was just about imagining something a bit different, something that could be the Targa Florio one day, Dalby Forest the next, a navigation rally, a rallycross, or just a freeform drive round the countryside.
So to finally answer your question, temporary barriers or bollards might well be useful.