Can I go there early, get tickets and park my car in a good spot, then walk off site and go get dinner somewhere via uber and come back?

No you cannot.

It specifically says no re entry. But you can get dinner to go and bring a table and have a date there. Or there's green area for a picnic that would be really cute. And if the bugs are a problem some people set up a tent. I also bring a bug Thermacell which helps a lot.

Thats a good question I've never done that before im assuming it says no re-entry so you might have to pay again