A lot depends on your site, your needs and your budget.
Golf carts are fairly accessible, relatively inexpensive and very adaptable. You will need to chose gas or electric (I've had good experience with gas but can envision where ele could work well) and whether to have an extra row of seats or a utility box. There are numerous types of tires available and you can certainly raise the vehicle for clearance, add roll bars, etc. or keep it simple. Since the gas pedel disconnects the parking brake these have the high risk considerations.
Gators are certainly more expensive but are great for maintenance (add a winch on front, powered tilt box, etc) and have a greater capacity. Generally slower but more stable in risky situations.
ATVs certainly have their place though extra training should be implimented. I used an ATV for trail upkeep at a site with miles of horse trails, anything else would have required wider trails and have been beat-up significantly.
Of course you could just use a truck or van, depending again on what you're trying to do.
Allowing campers, underage staff and anyone who you don't have documented site-specific training for shouldn't be allowed in anything other than a regular vehicle (car, van, etc.). Even maintenance-only vehicles should have writtenn policies & procedures regarding who is authorized, training & orientation, specific uses & inappropriate use, etc.
Hope this helps;
Phill
