Most policies will have no to limited coverage for these types of vehicles especially when being used away from your Home/Condo/Apartment. There are special policies you can get that will properly insure your off road vehicle wherever it is being used. 

Even though it is not a requirement to have Liability for your off road vehicle, it might be a good idea. What if you are driving fast on a trail and someone comes around the corner, you cannot stop in time and you hit them? Liability Insurance will pay for the bodily injuries you cause to the driver as well as pay the cost to repair their Off Road Vehicle.