Welcome! Try looking for "off road" clubs in your area. You probably won't find any Ranger clubs, and if your unfortunate enough to only have JEEP clubs then your probably S.O.L. as they tend to be kinda snooty to non-jeep drivers...
but who knows, better then not asking.
You might also look for any Rock-quarries that aren't closed off. There is one here and thats where I get most of my mud and fun. Just know the area as well as you can first to make sure you don't get into trouble, or damage anyone's property. And if your new, take it easy at first until you know your vehicle's limits.