1998 Dodge Roadtrek 190 Popular fresh water fill line

[JRBnGA]

Okay, I'm new. I may be doing this totally wrong, but maybe someone will inform me how to do it right. As the title states, I own a 1998 Dodge Roadtrek 190 Popular. I need to replace the fresh water fill hose. I can see 90+% of it under the unit. What I can't see and do not know how to access is the opening end in the rear door frame. This "end" seems to be pop riveted in the door frame. So, the main question is how do I access this end of the water fill line? Do I drill out those rivets and pull the line out from the top? Or, can I access the line where it joins the fill end inside the van body? If so, how is this done? If anyone can walk me through it by the numbers, or point me to a video, etc., I would be most grateful.