No 4 x 4 needed to get to WF. I drove up there from Denver on Wednesday and the roads were in great shape all the way. The snow is plowed right up to the boat ramps so just about any vehicles with good tires should get you there.
Agreed on the above. There is also the opportunity to park by the road by the inlet and just hop on down to the lake there. So even if you can't get to the campground (frequently happens for passenger cars, or during deep snow are worried about getting strranded down by the boat ramp, you can park near the inlet and walk the extra 1000 yards.