No to full sized beds! My husband and I have been sleeping in a queen sized bed since we got married almost 41 years ago. Sleeping in a full sized bed feels like we are in a twin sized bed!

It is even getting difficult to find bedding for fulls queens are always better.

A queen is definitely more comfortable/recommended, but most adults of a smaller nature could be ok on the full. I would tape out the space for a queen and decide if the floor space is adequate and look at different locations for the bed and reducing the amount of furniture, as not much is needed in a guest bedroom. As a host, I would be more comfortable providing a Queen size to my guests than a full, even if the floor space was made smaller. Mind you, sometimes I have to ask them to sleep on a blow up...so people make do!

I have a B&B. No one wants the full size bed. Most adults request a king. Go with the queen.

Since it's a guest room, the tight space won't be an everyday issue. Use small side tables and hang sconces. It will be cozy and comfortable.

All GREAT advise! I am going with the queens!