Making a sleeping porch

We rent a 100+ year old house here in Augusta, GA. I'm lucky enough to have a fully screened porch on the second floor. When we first moved in a couple of years ago I used it as my writing space the first summer, but due to how the sun moves during the day, I was pretty much forced to work with my table overlooking the neighbor's house next door. I could tell they weren't comfortable with that so I moved my office indoors and with the exception of setting up a spray paint station every once in awhile, we just haven't used this space at all since.

This is all I have for pictures of the room back when I was using it as my writing nook. I want to turn it into a sleeping porch. I'm not really sure on the dimensions. If I had to guess I'd say it's maybe 7-8 feet by 20, but I could be completely off. I'm horrible with distances.

My plans for this moment are to make curtains so that we can use the space without feeling like we're being creepy neighbors and to either find or build a twin bed frame that I'll put lengthwise along the wall where that fake mantel is (I don't know why that's there, but there is another one inside the house. I guess they just like the way they look) and use it as a daybed. Now in a perfect world, I'd like to have either a pop up trundle bed or else build a "coffee table" that can be pushed next to the daybed and keep a spare mattress under the daybed frame to put on top to create a bigger bed that will sleep 3-4 kids.

Has anybody done a project like this? Any advice, tutorials, inspiration pictures or anything like that to send my way? This is a hugely ambitious project for me. I am not much of a DIYer, but Pinterest gives me thoughts sometimes. At least until I attempt the projects I see. Then I remember how awful I am at that sort of stuff.