Years ago we used our old camper as a coop. It worked really well. It sat up on a wooden crate base with the stabilizers in place as well.
The hens would dust bathe underneath and enjoyed the shade under there.
The bed/loft (would be above truck cab) we used for storage of feed and bedding with a screen across to keep the hens out.
There were still cupboards in it so we took the doors off the lower ones for nestboxes and used the upper cupboards to store dusting powder, gardening supplies and such.
We put a roost where the couch/table had been. Gutted out the sink/stove counter area to give more floor space.
The best part was screens and locks on the windows to allow ventilation, but pest proof.
And ceiling vents too. We would just open the door in the morning and they free ranged all day, lock up at night.
With all the windows it was bright and airy.
At first glance you wouldn't even know it was a coop.