I've sent things to hotel guests numerous times. It's quite easy. ask the front desk for their postal address and ask them how the sender should write the address. Also, I think its actually safe doing it this way. someone else usually signs it for you and you either pick it up at the front desk or they can deliver it to your room... Just dont use your first and last name. Use your first initial and last name, (and/or room number if required) IF in doubt, call the front desk...