How does it make a difference whether you focus on getting sales through the website or use it for lead generation? Either way the focus is going to be customer acquisition.

Talking about your question header i.e. "I am doing driving tours from my car on the side for extra cash?" If I may ask, what's your primary revenue model?

Secondly, what makes you feel that your business is illegitimate? If it's unpredictable revenue then that's a problem of model and planning than legitimacy.

Thirdly, before you decide to take any further step, do you feel your business house is in order to leverage the same?

There could be many such questions to ponder. Let me know if I could help you with further clarity.