We just down-sized in August. I think it's important to have an extra bedroom where people can stay without you having to pack up all your stuff for the length of their visit. My sewing room can remain in whatever shape it's in and my projects are ready for me to pick up when I can. Hubby's space (in our case, it's a workshop) is in whatever condition he leaves it at the end of the day.
The prospect of having someone else sleep over doesn't bring with it the idea of having to pack up our projects, dust and vacuum and make room for their stuff. We stayed in a B&B in Europe that was the lady's computer room/piano lesson room - as a guest, I felt I had very little space (other than the bed) to put my things so the suitcase stayed open on the floor.
If you can manage it, I hope you end up with a genuine guest room instead of having to forfeit your space for visitors. We're in a one-bedroom townhouse condo with 2 extra bedrooms (one is my sewing room) and a workshop in the basement. It doesn't have to be big to still give everyone their own space.