Has anyone ever thought about laying some strut channel down in their bed between their 2x8 (or whatever) boards? I was just thinking it could come in handy for randomly bolting down anchors, attachments, etc. They have slotted ones that could help dirt and water fall out the backside. They'd probably be reasonable cheap if obtained from a plumbing or electrical wholesaler as opposed to the hardware store.

https://www.lowes.com/pd/SUPERSTRUT...lated-Half-Slot-Channel-Strut/1000192655