ROH or Run of the House or Run of the Hotel is a standard industry term and should not put you off at all. All it means is that you will be assigned a room based on what is available when you arrive as opposed to you being guaranteed a particular category (for which there is usually an extra charge). If you want a particular category of room and it will make a significant difference in the success or failure of your vacation - then you should be prepared to pay for it to ensure that you receive it.