1. Yes, LDW covers you completely without exception. There is no such thing as Super Cover in the U.S.
2. The upgrade does not apply to SUVs -- only to Economy through Fullsize cars.
3. Yes, if a drop-off fee is not specified, then there shouldn't be one.
4. Nope, it should be pretty straightforward. You should have an assigned spot upon arrival (look at the Gold board and/or check your email for a notification of what vehicle you were assigned) and just drive to the exit gate. It should be pretty simple and easy.

Have a great trip!

EDIT: Since it's your first booking with Hertz, you may be required to go inside to have them swipe your credit card. Hertz LAX has a dedicated Gold desk, so head there as opposed to waiting on the regular line if your name is not on the Gold board.