[Zeke]

That's a pretty large space for anything consistent. I think I'd design the roof top into zones and use different media area by area with some repetition to tie it all together.

You could use outdoor carpet in some areas to keep it cleaner. Some raised areas (wood decking) might serve as a place to park the lounge with maybe a bench at the perimeter with lift top storage. And some areas can just be coated with a lighter color, like the BBQ part for fire concerns.

Think along the lines of how oriental rugs look placed on hardwood floors and how furniture is sometimes arranged in small groups in a large room.

The existing roof must be repaired and sealed.