Essentially it would be an alum / alloy (same material as "no parking" signs)
There would be simple text - can be vinyl lettering reading whatever we wish
something like :
EAST CAMINO CIELO SHOOTING RANGE
CLEAN UP SCHEDULED BY CALGUNS
Then under that, we have 2 sections with 2x "holes punched" in the metal. The idea being we can have reuseable sheet metal "dates" like "mar, jan, jun, oct" etc.. plates for months, then a series of numbers
Those numbers would have the same 2 holes punched. We can then Zip-tie them to the sign to change dates and reuse the sign without wasting materials to designate the date.
Also @ the top of the sign i was thinking 2 "U" hooks - so we could just "hang it" on an existing forest service sign (like one of the many SMOKEY IS GOING TO HATE YOU IF YOU START A FOREST FIRE" signs - assuming the rangers are ok with this for the duration of the sign's posting)
and last but not least - literally mount a bicycle kickstand or something similar to the back of the sign if we need to play it in a position / hanging isnt available
sorry for short typing - works killing me, gunna be a 13hr day
Just another Boy and His Dog.