If we each only have 1 car then the games will be quick.
I could run 5 or 4 teams of 2 players with each player racing their car for 5 races each. This would cover holidays and other time outs. Teams picked at random by pulling the cars out of a hat.
Each race just 5 cars Race would last 1-2 hours so everyone could fit it in. Teams could race against each other.