I've ridden Greyhound before and no firearms means no firearms, including for CCW. Some (but not all) Greyhound stations, particularly in large cities, do have security checkpoints that you'll need to pass through before boarding the bus. Unlike at airports, different bus stations have different security precautions, so you'll need to know what it's like at each different stop if you're going to pull it off successfully. Since you don't, I'd recommend just leaving your gun at home. You're better off just renting a car and driving yourself.