Not unusual, since Roadtrek had to reposition some gas tanks, forward or back, back then to allow clearance for other appliances, most notably, the Onan generators. My 190P had something similar, and it's because the fill pipe is often bent and/or tilted diagonally left or right. If you can rotate the pump handle left or right, you might get better results when filling. Finding your best angle of attack that works will be trial and error.
Your theory may also be possible, but you have to go in through the outside storage compartment (at least in my 2002 190P) to access the fill pipe. There's a removable panel near the rear end of the driver's side external storage compartment (again, in my 2002 190P).
2018 (2017 Sprinter Cab Chassis) Navion24V + 2016 Wrangler JKU (sold @ ????) - 2016 Sunstar 26HE (sold @ 4600 miles) - 2002 Roadtrek C190P (sold @ 315,000kms)