How to Rat proof my bedroom.

I have 3 female rats that are super affectionate and cuddly. They’re 3 1/2 months old. I recently redecorated my bedroom where their cage is and where they get their free range time. I made an accordion collapsible cardboard “pen” out of cardboard and duct tape that I place around the cage and keep those vinyl tablecloths on the floor for easy cleaning after playtime is over. I would really like to just place the “pen” across the openings on each side of the bedroom (it’s an open concept style apartment so the bedroom area is in the middle) and just let them enjoy being out in the room instead of confined to a play area. For you more experienced rat owners who regularly let your rats out into large open areas, how do I go about protecting things they could ruin or get injured on like electric cords and chargers, bookshelves with framed photos etc? Also do I need to worry about them scent marking or peeing everywhere? There’s carpet in the room and I’m wondering if it will begin to smell. Any help or knowledge would be appreciated, as of now they will keep using the play yard until I can figure this out for the benefit of all. Pics for Rat Tax.