Had a water leak today

Actually OSB is more water resistant than conventional plywood because of the resins used to hold it together. Having said that you do want to make sure it gets dry as quickly as possible and if there is damage you may have to use CPES to coat the wood. You did not say where the leak was if in the walls this is a serious concern. You southern folks do not normally concern yourself with winterizing but with the increasingly freakish weather which is likely to increase you should at least blow out the lines with compressed air.
Our trailer was winterized once school started (wife teaches) and lines blown out and antifreeze added. Looking out the window it is snowing now.