I would Tidewater is definitely the group to join they are an awesome group of people and do an amazing time at Oak Ridge and other events. If you are looking for a real club to join go with them.
If you are looking for a group of offroaders that like to hangout and go on rides but nothing is an official club, you could try VOW, Virginia Offroad Warriors. It is mainly a Facebook group but we have members from all over the state. We have done rides at Oak Ridge, Jeep Jam, Potts Mountain, Shoe Creek, Big Levels, and Flagpole all within the last 3 months.