Get a wireless RH sensor so you can monitor the crawl space RH from your kitchen. Seal up the vents and get a dehumidifier with a pump or drain hose. Vapor barrier on the dirt floor. Typically dehumidifiers for crawl spaces are higher capacity and more efficient than the normal dehumidifiers you find at Home depot. It may take several days to bring down the RH. You can get mold and wood decay if the RH gets into the 60% to 70% range. Try to get it to 45% to 50%.
I would pour concrete. Maybe you can find a handy neighbor to help
I would pour concrete. Maybe you can find a handy neighbor to help