All of the first come first serve places have a box to drop your cash into with an envelope. We do it all the time and if you want your pick of the best spots get there by Thursday and pay for it thru the weekend. There is also usually a marking post at each site that you can tag if needed.
some new rules if you camp along the road for foster and greenpeter dams you have to have a honey bucket
don't know if it extends up the mining corridor but is always a good idea.
and with fire season carry an extinguisher or 2 gallons of water and a shovel.
no smoking outside of your vehicle, or light up as you go talk to the ranger. ??