Hi Susan,
I noticed that you have two listings. I am assuming that these are the two rooms that you are talking about? If so, to me all looks good. If you want guests to have the option of booking both rooms together, you need a third listing. Then you will need to be sure to block individual room dates that get booked as a double room. Do not do instant book for all the listings - keep either the single rooms or the double room listing manually controlled to prevent double bookings.
I wouldn't worry about guests needing to scroll down to see both rooms for that listing. Something has to show at the top.