Welcome to iRV2. I've used a strong solution of hydrogen peroxide to clean the fabric roof in my coach.
Cover anything you don't want white. Start with a small area , spray on and allow to dry , vacuum, re-treat if required.
99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 3060
2000 Caravan toad, Remco & Blue Ox.