It depends what you want to drive on it, how firm the soil is and how much you are happy to spend to be confident you won’t have ever a problem, or whether you’d prefer to save now and patch it up if an when it was a problem.
The fabric will be a geotextile like Terram, designed to stop the soil migrating up into the gravel. Hardcore will do that as well but isn’t necessary if the soil is firm any you’re only running cars on it.
If you’re in England (there may be similar rules elsewhere), bear in mind the planning rules for drives – you have to make sure water will drain away and not onto the road:
http://www.planningportal.gov.uk/permission/commonprojects/pavingfrontgarden/