We have a '92, 29' Classic/Excella with street-side kitchen, center bath, rear twin beds. I've not needed to access the fill hose, and our layout may be different than yours. On our trailer I think I could gain access by removing all the drawers, removing the slide-out pantry drawer, or perhaps removing the bottom of the closet. It's definitely tight space.
If you can see (or feel) the end of the hose where it attaches to the tank maybe you can watch (or feel) as somebody else fills from the outside and find the leak.
We had a similar problem on our 1998 B190 Airstream van and we just started removing drawers and panels and such until we were able to access the hose to remove and replace it.
Lucius and Danielle
1992 29' Excella Classic
1996 GMC Suburban C2500 7.4L
2005 Chevrolet Suburban K2500 8.1L
Got a cooped-up feeling, gotta get out of town, got those Airstream campin' blues...