We ate at CG in January; we waited 50 minutes past our ADR time to get a table as they frequently really back up the closer it gets to Wishes as people do not want to leave when they are done eating--they linger at their tables for the fireworks. It is very common here to wait past your ADR time but our Jan trip was the longest wait we've ever had here. There was no place in the lounge or bar to sit and there were probably close to 50 people standing by the elevators in very close quarters waiting for their tables. Once seated, Our meal took every bit of 2 hours so MK was long closed by the time we were done with our meal.
You will be allowed up and can go out on the observation decks to watch the fireworks, even if you have not gotten your table yet. Do not count on getting a window seat where you will have good viewing for the fireworks. In the 5+ times we have eaten here, we've only had a good window table once. All other times we've had to go out onto the decks to watch. The servers will hold your courses to accommodate this.
We took a cab from CR back to BC on this last trip. For the $20, it was worth it to not have to ride buses.