I have a 2003 Dynasty 38' - the gravity water fill hose was rotted.
This is where I found a replacement:
https://www.amazon.com/Flats-Concess...7&sr=8-49&th=1
The 3' length might be enough, but I would buy the 10'.
I found that the access was the biggest problem. I took the fill plate off the outside of the MH and was able to reach in and loosen the hose clamp and then remove the old hose.
The replacement hose is flexible kind of easy to tear (thus, the recommendation for the 10' in case you ruin a section).
I was going to try to use some heavier duty tubing, but what I found was either not flexible enough or kinked when bent.
Defiantly not a major repair. Only took me about an hour.
Jim