For potable drinking water, use a hose certified to NSF-61 which will be free of lead, BPA and phthalates (and some other contaminants). Don't get a PVC (vinyl) hose, get a polyurethane one. Also, some people are highly sensitive to the taste of vinyl hoses. Other considerations might be pressure drop for a long hose run (use larger dia.) and burst pressure rating (pressure rating usually goes down for a larger dia. but could use a pressure regulator at the CG faucet).
You likely won't develop a life-threatening illness from the occasional sip from a garden hose but for regular ongoing drinking and cooking in an RV why take the risk. Flushing a hose can help, esp. if it's a long run sitting in the hot sun.