I'd build a scale replica of a real dirt oval. A 1/32 scale mile is (5280/32) 165 feet. A scale 3/8th mile oval would need to be 62 feet around. I thought about building a 1/4 scale mile oval in our attic where there is space for the 9' by 18' table this could fit on, but it's too cold in the winter and too hot in the summer to be practical.
To be like actual dirt tracks I enjoy, the track would need to be wider to accommodate the sweeping turns most tracks have. Check out some aerial photos of tracks and it becomes apparent they aren't paperclips like we can imagine from the stands.
Eldora speedway (1/2 mile banked dirt track):

I'd scale the above layout down to 3/8th of a mile in 1/32 scale, and replicate with 3 routed lanes, each following realistic racing grooves drivers use. And, if issues with lane change switches could be resolved I'd make it digital using a system where from 6 - 12 cars could race at the same time with each choosing their desired lane twice a lap, probably at the entrances or exits to turns.
Only thing missing would be a machine to blow dust in your face and engine sound effects like with model railroading so you might want to get ear plugs.
Slothead