Nice job <img src="/forums/images/graemlins/kewl.gif" alt="" />

Replacing the wood with plate will just add more weight to the gate, and allow for more noise, the wood will help absorb any noise made by the tools.

I would use a thin piece of aluminum diamond plate and attatch it to the wood with the smooth side up. This would give you a smooth surface and the wood behind it would give support to the aluminum when being used as work bench or seat.

More than tread lightly. Leave it like you were never there, nor anyone else.
'90 X-cab 4.88's 33 BFG AT's, rr ARB, Headers, Ignition upgrade, cold air induction.
'91 X-cab 5.29's 315's BFG MT's, rr ARB, custom bumper and flatbed