IMO the key for "stealth camping" is to simply blend in with your surroundings. An NPR box van, a Sprinter Van or a "Snap On" van would blend in almost anywhere. Why worry about stealth when you have security through obscurity?
Park in a shopping center, a school or church, a motel parking lot or a truck stop or a rest area and call it good. If you are concerned about being bothered make up some magnetic signs with a service company or a bakery or some kind of charity or foundation name on it. Unless you are acting the fool, no one will likely bother you.