Gas smell inside

I have a '96 chevy blazer V6 4.3l engine and just recently started smelling gas in the inside. Also gas milage has decreased. I suspect the fuel pressure regulator from what I've researched so far but still unsure of that. EGR has been replaced and truck ran fine after that for awhile. This appears to be a new problem. My question is Where is the fuel pressure regulator and is there a way to check it before i invest 60 bucks in a new one. Or if anyone has any other causes I'd appreciate your input. Thanks!!!

What makes you think its the regulator?
I would look around with pressure on the fuel system to find a leak, most likely in the front of the vehicle someware.
My first guess would be one of the fittings has rusted and gets a slight leak under pressure.

My 96 blazer smelled like gas inside the cab for a long time, then the check engine light came on, I hooked up the code scanner and it said the gas cap was bad, I replaced the gas cap and the smell inside the cab disappeared.

Gas cap wouldn't affect gas mileage, at least I highly doubt, but you may want to look into this for the smell issue. I have heard of leaks in th CPI fuel system dropping gas onto the mantifold, resulting in ruff idle and bad gas milage, a fuel system pressure check will determine any issues like this. But for 7 bucks ( a new gas cap ) I resolved my fuel smell in the cab issue.

Sounds like a fuel line leak somewhere, get it checked out before you have a fire.