William,
I am not looking at your coach, but since you are talking about the hose going through the coach floor, I assume that the hose terminates inside the coach. If so, the hose is usually sealed with foam, so you can usually get to the location below the floor to cut out the foam and pull the old hose below the floor and run the new hose back through the same hole. As for drilling another hole, since the area that the hose needs to fit into is very limited, that is probably not a good option, but if there is enough room and you can not get to the old hose below the floor, why not? To give you a definite answer, I would have to be looking at your coach.
Gerald