@Mark-and-Kerry3 if you market two rooms then you have to set up for two rooms. The number of guests is actually irrelevant. If you want to only make up one room then create a one room listing and price it accordingly.
I have a 2 bed apartment and I have couples who use both bedrooms so unless you want to enter into their sleeping preferences (I certainly don't) then you should make up both beds.
You will get lucky of course and find that second bed untouched but that's the reason why I have the same price whether you're 2 guests or 4. I always double check the correct guest count when they book to be sure of the number of towels required.