I was able to cut some pieces of Corian from the remaining large "Island" piece and make them fit up to the other Corian. I also decided to line the cavity where the Egg sits with corrugated tin like on the roof. Very good decision I think.
The cabinet to the left of the Egg holds large grills and assorted items for the Egg.
I celebrated the occasion by cooking two steaks on the Egg. Worked perfectly.
I hope to finish up the remaining cabinet for the Small Egg by this weekend so we can paint.