Soak his feet in lysol/water mix maybe 10/90 ratio or 20/80 for 10 minutes each once. Then wash daily using a stiff bristle brush with lysol/water or sunlight dish soap/water; rinse, dry and apply antifungal cream. I personally use 1:1:1 of athlete's foot cream, triple antibiotic cream and zinc oxide cream.
You might want to soak his feet again next week, but don't go crazy on the soaking.
If his toes are still long, don't wait a month for another trim. Another farrier might be called for as well, depending on the situation. Feel free to post pics of his feet.
The stocking up could be from standing in the trailer too long, or being stalled too long before transport. Is there heat? If so, you can cold hose for 20 minutes once or twice daily. Don't keep him stalled -- let him have full movement.