2013 Chevy Equinox Gas Tank Access

Hey there. Doing one of my first jobs as a mobile mechanic. The customer has the vehicle in the title, and so far I've narrowed it down to the low-pressure in tank pump (fuel pressure read ~1 psi, emptying feed line into a bottle and there's an obvious blockage downstream, compression test within spec)

Customer suspected antifreeze in their gas tank. They had a mostly full tank, but nonetheless it just cranks no starts.

Question I'm asking is there anyway to access the top of the tank or the fuel pump, from the backseats or interior? I'm doing this job nearly for free, so I'd really hate to have to drop the driveshaft, exhaust, then wrestle a nearly full gas tank down. Thanks.