Per :
WRC will go bad eventually but you will get 10 15 years out of it
before it really gets bad

I have a rough sawn 2x12 as a walk board on my boat trailer that has
been in the weather for 10 years, occasionally dunked in salt water
and it is OK but looking weathered.
Lower right of this picture
http://gfretwell.com/ftp/trailer.jpg

I think I'll go with just letting it weather then.

10-15 years is more than enough. I'll let my survivors worry about the
rest.... -)
--
Pete Cresswell