WEEEELLLLlllllll.... If you Drive into the Themepark I'd expect at Minimum a night in jail, some pretty nasty charges, and who knows what kind of legal fees and fines you might end up getting.
It's much cheaper to drive into the park's parking lot and then walk into the Themepark. Disney and Universal are both charging $14/day currently to park your car in their lots.
You get free parking if you're staying on-site or have an AP.
Also, you can parking lot "hop" - meaning if you pay the fee at one park and decide to drive to another, you don't have to pay for parking again at second park. Just show your receipt at the gate.