I finally got the particle board put in under the sink. It definitely looks like a patch job, but it costs way less than replacing the whole cabinet. The notches down the center are pocket holes. The whole board couldn't fit in with that vertical bar in front. So I cut it in half, then used the kreg jig to out it back together. Now that it's no longer a hole to the foundation, I'll be able to crawl under there to replace the kitchen faucet sometime soon.
