I'd go with an adjustable heat gun being very careful not to melt the hose. A second option would be to use a heat cable under it and a blanket over it. All that said, if you don't have an adjustable heat gun or a heat cable of that length it's probably going to be cheaper to buy a new hose than either one of those.
Dick, Joyce, Diego, Picatso and Gustav
2017 3720 RL, and 2013 HC 343RL
2017 3500 Dodge Maxi DRW 4X4, Pullrite Hitch, IS, Disk Brakes, 3rd AC, Winegard Traveler, Bathroom door mod, Dometic 320, couch for desk swap, etc.