You have me confused again, FD. Thought teaching your son racing was a key part ?
An owner of a porsche has no interest in "beating" some old BMWs.
That's like suggesting the owner of a michelin star restaurant would want to eat at McDonalds !!!!
I did likewise what you had in the past, just there were 10-12 of us and we learned to repair/fix as well
BUT there are better ways ( and safer given the possible speed of more modern machinery ! )
I will close on what I suggested at the beginning. Sort out your business idea, your plan and research it properly. Because now you are suggesting a "club" which then hires tracks all over the US for folsk to drive on. WHY on earth would anyone pay a large sum to be a member to join that club when there are so many doing the same task without "membership lump sum". AND if you follow this "new" plan through then you run out of money half way through year one and as you said it woudl then be "free" for members to take car on track you will quickly be taken to court for failing to deliver to contract
Only way to sucess is research, research, research.
Only in bad tv movies do "ideas out of the blue" work