Can someone enlighten me on the rules for which roads we can drive on in the Little Missouri National Grasslands. Had a warden harass us a couple weeks ago and told us he was "pretty sure" we couldn't drive the numbered FDR or mapped two track roads when I ran into him and asked him about access to some locations and that we should use the Motor Vehicle Use Map (MVUM) to know which roads we can or can not use. I was using Onx. I can't find a current MVUM anywhere online and the Find Your Adventure Forest Service App is worthless for this. I was under the assumption that if it was a number or named road or two track, you are allow to drive it as long as there isn't a fire restriction on those roads. I called the watford city Forest Service Office and asked them and he told me we could drive those roads but it took him a while and he didn't seem very sure of himself. Seems like the people that should know the rules out there don't really know them for certain either.