Most campground have a water spigot fairly close. If it is not, it usually is not yours or is for public use. There are a few exceptions but not many.
In direct answer to your question,
* You want an RV drinking hose, not a common garden hose.
* A fresh water hose is usually blue or has a blue stripe in it and is made from non-toxic, low odor material.
* Fresh water hoses are use only for providing fresh water, not flushing your dump tank slinky or washing your RV.
* Two 25 footers is all I ever needed. Two A 25 ft. and a 50 ft. are far more handy than a 100 ft. hose.
Yes I certainly drank my share of water from a old garden hose growing up but if you recall, you let it run until the water was cooler.
When camping your hose can lay in the sun for hours. If the funky tasting garden hose water get into you RV system and can be quite annoying.
If you are new to camping, take suggestions about what you cannot live without with a caution. I still have a couple of products that "no camper should be without" still sealed in there original containers four years later.
Safe travels