Cross Country and bulking? Maybe your best bet is to simply try and maintain by eating like Michael Phelps.
It's not even just about burning fat from all the calorie expenditure of running. In whatever stresses you put your body under, it will do its best to become efficient at dealing with that stress. In long distance running, a large element of making the body more efficient at what it's doing is to lessen it's weight load. Given that muscle outweighs fat tremendously, the first it WANTS to let go are the body's natural anchor's aka muscle. In cross country, you're not only burning massive calories, but your body will specifically target muscle, as they are seen as an obstruction to optimal efficiency of long distance running. Short of long, lean leg muscles, your upper body will naturally be eaten up.
Again, short of eating like a beast.