Linseed oil is a very poor moisture protectant for wood. Over a relatively short time it evaporates and oxidizes, leaving the wood unprotected. Even indoors, it regularly has to be reapplied to remain effective.

If the flooring is covered with mats and regularly cleaned, it can last as long as the trailer. We had a wooden stock/combo trailer with an untreated wooden floor. When it was sold after over a decade of hard usage, except for paint over spray due to a restoration, the flooring looked like new. After every usage, we used to roll the butt side of the mats inward, and flush the floor and wall joint with a garden hose.

Many oil based wood protectorants are available for wood sealing. They are commonly sold for decking, fencing and most notably, for log home ownership. They are low viscosity products that penetrate and absorb into the wood cells, where they dry and seal the wood fibers. Because the flooring is more protected from the sun's UV damage than their regular external applications, these products can be long lasting. They are first applied in multiple applications, flooding the wood until it can no longer absorb any more of the sealants. Subsequent applications are easily added, after a cursory cleaning of the flooring.

Latex based product are surfactants, do not penetrate deeply into the wood and are subject to mechanical damage. To reapply, the original surface coating often has to be firstly removed.

The best sealant is also the most expensive. In the marine industry, epoxy coatings and adhesives are use to encapsulate wood products. They effectively block any moisture from reaching the wood. They are absorbed into the wood cells and then chemically harden to form a waterproof barrier, whilst mechanically strengthening the wood.

 There is one manufacturer of bed line materials that is marketing its product for usage on wooden flooring. Dupli Color's "Bed Armor" is being sold to protect wooden products. It is the only manufacturer of which I am familiar with, to do so.