When you open the fuel door to fill the gas tank, there is a rubber piece that surrounds the filler pipe. Beneath that surround there are three braided type fuel vapor lines that go into the trunk.

You might be able to see the lines from underneath the car but it's really pretty easy just to pull up on that rubber piece to get beneath it.

A rodent had chewed into two of the lines. I replaced them with some rubber fuel hose I had laying around and no more gasoline smell!

Took about one hour, a few dollars of fuel line and a couple of hose clamps. Good luck!