I carry two 25' 30 amp cords simply because I had one and the current fiver came with one. Never have needed both, my permanently connected 50 amp cord is also 30'.
Extra water hoses are a must. Right now we have 100' since we have two older 25 footers and two new ones we have not used yet.
Last fall in Colorado I had critters (ranger speculated prairie dogs) chew through two water hoses in a week! When the first one sprung leaks, I assumed it was just old. The second one happened on a cold night when the hose was disconnected and lying on the ground so the bite marks were obvious.
Usually two sewer hose are sufficient, but there have been occasions where I needed three. Nice to have a spare there as well.
