I've finished all of the fun wood-centric portions of the PCEI bridge.
I laid 5' wide 2x6 Western Red Cedar decking across the stringers and attached 2x4 cedar boards on either side:
I applied two quarts of AFM Naturals Clear Penetrating Oil to the entire deck. I purchased this all-natural penetrating oil at The Natural Abode here in Moscow. This penetrating oil is made almost exclusively from organic plant oils and contains no heavy metals or other hazardous driers.
This penetrating oil will help keep the wood supple and healthy. It will retard absorption of water into the wood and keep the wood more dimensionally stable.
Here, you can see the deck is still wet with oil:
A side view of the completed bridge:
And some miscellaneous pictures of the bridge shown below. Overall, I think the bridge turned out nicely!
The next step involves mainly rock, gravel and dirt. The plan is to build compacted, natural earthen ramps up to the bridge from either side such that the grade is continuous up and over the bridge.
This will be useful for walkers and crucial for bicycles, wheelbarrows, and wheelchairs that will use this nice wooden bridge.