Updating for posterity.
We were able to get this fixed, it wasn't super simple, but it wasn't the most complicated either.
After unscrewing the gravity fill well thing, we could see that the tank was right there - unfortunately, the hole was too small to do anything about it.
After picking up some new hose to replace the shredded hose that was there (ours was 1 1/2" flex hose), we removed the front passenger sized wheel and jacked up the rt (you could use leveling blocks).
From there we could see a vacuum pump that I believe was part of the chassis system, that we removed to gain access to the tank. Once we had access we were able to get the new hose on the barbed tank connection, resecure with a hose clamp, (return the vacuum pump), and finish the install on the gravity fill well from just inside the passenger door.
Hope this helps if anyone else runs into this situation :)
