If your gas cap matches the ignition then you could always try and take it to a locksmith to see if he can make one. I would also take the title with it to show proof of ownership.
There is also a way to remove the rear seat without breaking anything. Here is a link. Try at your own risk.
https://www.youtube.com/watch?v=9PlUOQX6XCY
There is also a way to remove the rear seat without breaking anything. Here is a link. Try at your own risk.
https://www.youtube.com/watch?v=9PlUOQX6XCY