Rout the lettering, then spray paint the letters, not worrying about getting it on the surface around them. When it is dry, sand the surface of the sign to remove the paint from all but the letters. Then use a roller with just enough stain to stain the board surface, keeping it out of the letters.
Another way -
Stain and finish the sign blank. Then, cover the entire board surface with packing or blue tape. Rout the lettering. Then spray paint the routed lettering. When it's dry, remove the tape and the sign is complete.
I've done it both ways, but usually prefer the second method. Good carbide bits will leave clean and crisp lettering, requiring no sanding.
I work in a park too, but mostly drive the train that you can see in my avatar and fix the park electrical problems, but have also made signs.
Central North Carolina
Last edited by CharleyL; 08-20-2019 at 05:55 PM.