How many keets is the 1st question. I had one sleep quite happily in hers until she was 8 mo old, but she was inside and not in the box all the time. (She was in d/t being a late single hatch going into winter; she now is outside w/the rest).
I currently have 7 living in the same box, 4.5 wks old. They are transitioning to the run during the day.
So that gives you a month or so install a coop and secure run.My 1st batch were inside - also 7- for abt 8 wks waiting for their coop/truck to be done. Hint - don't take that long.

Don't turn them loose at 8 wks. It sounded reasonable, until the bulk of the hatch was dissappeared in a matter of minutes-and they were with their parents.
Our first coop was/is stupendous. He built it himself, 6'×10' "truck/tractor" - 1/2 coop, 1/2 run. I put a small fan inside and it stays cool. In the winter,I cover the run with clear polycarbonate panels, they have a sun room. Problem is, getting guineas means getting more guineas whether from mating or because you fall inlove w/them and want more colors. So we needed another coop and larger run. He built the run, and- I think we should be calling these things atriums. We're not talking mucky ole chicken run.
But he didn't want to spend 2 months building another coop. So we bought a shed to convert into a coop. It's much bigger-8x12.5. It's easier to clean...and it's hotter than


. So we put an 18" outdoor fan in it,covered the top with silver tarp to reflect heat and another tarp to act as on awning over the west window. It's much cooler now, but he's going to put more venting in the roof where the skylights are. All it takes is time.

As for free time at 8 wks, I use an octagonal shaped covered dog kennel. At 8 wks, only a runt will be able to fit between bars (had one), but once out they'll desperately try to get back to the others. It's a good way to acquaint them to the outdoors safely. When the weather/temps arin the 90s, I also use what I call a playpen for 3-4 wk old keets to take them outside during the day. It's a nylon pop up with mesh windows and a zip top- they have bigger ones for dogs but this is shorter. $20 (ish)
You'll be the one training them to return to the coop before dark and locking them in.