I always check in with the local Ranger District office before riding on National Forest roads. There always could be closures, construction, hauling, fires, grizzly bears, snow, hunting season (lots of hunters shoot from their vehicles illegally), etc. that may change your choice of road. Also, they would know where to start looking for you if you don't show up at home.
Definitely this! Some roads may be closed for certain days or closed before a certain time during hunting seasons. For us in Georgia, it affects our gravel and mtb riding from about Sept.-Jan. Know which ranger district the roads are in.
As far as equipment, I ride the same gravel bike regardless of where I'm riding. If I'm doing a MTB or gravel back country ride I make sure to take extra water with me--maybe my Camelback--and extra food. I make sure my cell phone is 100% charged in case I can get a signal if I get in trouble. I also wear a Road ID in case something happens.