How to get to gas tank top (fuel pump & evap connectors) in a 2018 Wrangler JKU without dropping the tank

Although I've never cut an access hole in a Jeep, I've done several pickups over the years. If there was ever a vehicle that needs one, it would be one that goes out in the middle of nowhere. I'd definately cut an access hole if my pump went out. Drill a hole and go at it with a pneumatic sheetmetal nibbler.
 
You can cut a hole in from the top, but I think dropping the tank is probably your best bet. Just be sure to have it supported by a good floor jack, because it's almost certainly going to be heavy, unless you get it totally empty before you start.

I agree, drain tank, then drop it..it will be a lot lighter. Who wants to cut open the jeep floor to get to the tank..more work.