Disclaimer: As was recently noted here, I've never owned a raceway so you can take the following suggestions with a grain of salt, if you so desire.
First, the key idea you must embrace is that a slot car raceway is an entertainment business, not a racing business.
Second, one of the hardest tasks will be to balance a number of different revenue streams, such as:
the "walk-in" who may only come in a single time just to give slots a try
the "partier" who wants a hold a fun event for the invitees (birthday, corporate, or otherwise)
the "player" whose main interest is in the casual leisure-time diversion of running his slot cars
the "racer" who places much (sometimes too much) importance on winning races (and this class is further subdivided into the different kinds of slot cars)
It varies from raceway to raceway which "class" of customer will provide the largest revenue stream, but I think it is accurate to say that in most raceways it is not the "racer" who generates the most revenue.
Achieving the necessary balance is not a trivial task, as factors that are important to one group are often not as important to other groups. For example, "racers" largely won't be concerned if the facility is a little grungy and the bathrooms less than spotless, but you can bet that the "walk-in" and "partier" groups almost certainly will.
As a businessperson, it will be important for you to understand the concerns and desires of all customer classes and to be equally welcoming and accomodating to each one. That's assuming the intention is to have your revenue cover your costs to the greatest extent possible.