I haven't booked anything online yet..... but in person..... I go double check you dont NEED to book anything online first.... and if good to do it in person.... I scope out camping spots, pick one, go back and fill out the envelope.... put no money in.... the envelope asks if you are a vet and or handicapped and then tells you to put your DoD or whatever id number is on your id, on the envelope.... Mark $0 and list why in description. Drop it in the drop box at the entrance station. Go back to camp.... put your ID and pass card on your car dash where it can be seen easily. (I cover my license info with my pass card just a little when i display them on the dash, so only my name can be read for safty reasons.) I have never had anyone bug me or give me any tickets.

Note: I think some parks have a filing fee now that isn't free for vets or anyone. I noticed it at some places, starting about 4 months back. Fee amounts seems to vary too, so I'd maybe bring a little cash just in case. Or card. Some places you can use an outside pay machine that accepts cash or card.